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Whey and Pea Protein Fortification of Rice Starches: Effects on Protein and Starch Digestibility and Starch Pasting Properties
... Water loving groups called hydrophilic groups present in starch and protein has a great effect on WAC and this increasing WAC with increase in mungbean proportion could be attributed to improved hydrophilic amino acid fractions in blend. These hydrophilic fractions have a strong affinity towards water molecules, which explains why high-protein foods absorb water efficiently [5,34]. Oil absorption capacity (OAC) is the assessment of oil entrapment and retention in the capillaries of flour particles. ...
... This rise could be attributed to the protein fraction which is soluble and is believed to be increased with the addition of leguminous flours which probably would increases solid loss [41]. Sharma et al. [34] and El-Sohaimy et al. [39] also suggested that more solid losses occurs when gluten-free materials are added. Cooking losses of less than 9% are normally ideal. ...
... As a result, it's critical to comprehend the activities that take place when rehydration of pasta occurs while cooking, which is a complex process of mass transport driven by many mechanisms of water migration into the pores. Optimal cooking time is considered as starch gelatinization to a degree, when center of the pasta is optimally cooked [34]. Results presented in Table 2 showed that the control (barley pasta) pasta exhibits highest cooking time (6.01 min), which reduced significantly (P < 0.05) from 5.36 to 4.54 min as the substitution level of mungbean flour was increased from 10 to 40%. ...
The present study investigates the influence of mungbean flour at different levels (10–40%) in barley flour-based pasta on functional, pasting, cooking, textural, color, bioactive, molecular, morphological and structural properties of the resultant pasta. Results showed that mungbean substitution altered the pasting viscosity of flour blends while enhancing its water absorption and oil absorption capacity. Substitution of mungbean in barley produces pasta that exhibits a reduced cooking time and increased cooking loss in comparison to barley pasta. The increase in mungbean flour level in the pasta increased the protein and fiber content. Pasta with higher mungbean substitution exhibits increased in lightness (L*) and yellowness (b*) value, while redness (a*) value and browning index decreased. Mungbean substitution in pasta increased its antioxidative properties and bioactive potential by enhancing the total phenolics and flavonoid content. Cooking of pasta however modulates the color, antioxidant and bioactive potential of the pasta. Presence of characteristics peak in FTIR spectra with a strong absorption band between 3200 and 3300 cm-1 confirms the presence of phenolics compounds in the mungbean-supplemented pasta. SEM reveals that the addition of mungbean flour impacts the structural integrity of the pasta owing to the increased level of protein and fiber and results in a weaker matrix, which was also confirmed by decreased firmness and toughness of pasta. Sensory studied showed that pasta with mungbean was better acceptable by the panelist in comparison to barley pasta (control) and pasta with 30% mungbean exhibits highest score in all sensory characteristics, consequently showing the mungbean potential for pasta production.
... When the starch:protein ratio was 90:10, the pasting temperature increased to 78 °C and for samples with a ratio of 60:40 the pasting temperature was 90 °C. Higher protein content in starch:protein gels has previously been associated with augmented pasting temperature and reduced gel firmness Joshi et al., 2014;Núñez-Santiago et al., 2004;Oñate Narciso & Brennan, 2018;Onwulata et al., 2014;Ribotta et al., 2007;Yang et al., 2004). In lentil starch:protein mixtures, delayed pasting associated with protein incorporation has been related to the overall higher denaturation temperature of the protein, which is essential for heatinduced gelation (Joshi et al., 2014). ...
... In a study adding 10% extra protein, breakdown of starch-protein mixed pastes was no longer detected, suggesting that the protein gel network increased the resistance to mechanical shearing (Joshi et al., 2014). During cooling of starch dispersions, gelation occurs as amylose and amylopectin aggregate to form a gel network, but higher protein content has been found to correlate with a reduction in final viscosity Joshi et al., 2014;Oñate Narciso & Brennan, 2018;Onwulata et al., 2014;Ribotta et al., 2007). The amylose:amylopectin ratio in starch has been shown to have an effect on the viscosity and gel strength of composite gels, with the reduced viscosities associated with incorporation of protein being more pronounced for high-amylose starches (Joshi et al., 2014;Oñate Narciso & Brennan, 2018). ...
... During cooling of starch dispersions, gelation occurs as amylose and amylopectin aggregate to form a gel network, but higher protein content has been found to correlate with a reduction in final viscosity Joshi et al., 2014;Oñate Narciso & Brennan, 2018;Onwulata et al., 2014;Ribotta et al., 2007). The amylose:amylopectin ratio in starch has been shown to have an effect on the viscosity and gel strength of composite gels, with the reduced viscosities associated with incorporation of protein being more pronounced for high-amylose starches (Joshi et al., 2014;Oñate Narciso & Brennan, 2018). Studies by Oñate Narciso and Brennan (2018) and Onwulata et al. (2014) revealed that proteins appeared to prevent molecular rearrangement of amylose, resulting in weaker gels. ...
Faba bean (Vicia faba minor) is a cool-climate crop that could serve as a locally sourced sustainable ingredient in transition towards a more plant-based diet in temperate regions. Poor texture is one of the main aversion factors of plant-based foods, so this thesis characterised the functionality of faba bean components and their effect on structure and texture in different food matrices. The main aim in this thesis was to increase the knowledge on structure-texture relationship in increasingly complex faba bean food prodcuts. Isolated faba bean fractions (starch, protein and fibre) were studied. Faba bean starch was physiochemically characterised and microscopic and macroscopic properties were correlated. Different ratios of starch and protein were then combined to create mixed gels. Faba bean starch formed a relatively viscous paste due to long branch-chains, high amylose content and larger granule size. Addition of protein perturbed starch network formation, delaying and reducing associated pasting and gel viscosities in mixed systems. For food model systems, two prototypes were designed: i) a combination of faba bean starch, protein and fibre to produce edible ink for 3D-printed foods and ii) faba bean protein films reinforced with cellulose nanocrystals (CNC) for use as bio-degradable edible packaging. For the 3D samples, fibre appeared to have a stabilising effect on structure, improving ink printability while also ensuring that 3D-printed objects retained their shape. Carbohydrate-rich 3D-printed objects had a more porous structure that required less force to compress than structurally more compact protein-rich objects. Addition of CNC resulted in stronger, stiffer and more opaque films with improved barrier properties. Thus faba bean fractions in different combinations and processing approaches yield different textures. Using the basic knowledge of component functionalities in simple systems obtained in this thesis, intra- and intermolecular factors influencing product texture in more complex systems can be assessed.
... In brief, concentrated starch gels can be described as a composite system consisting of swollen granules embedded in a three-dimensional network of aggregated amylose chains (Yang, Irudayaraj, Otgonchimeg, & Walsh, 2004), while globular proteins form fine-stranded gel networks at high repulsion or a coarse-stranded network of colloidal particles as the isoelectric point is approached (Langton et al., 2020;Langton & Hermansson, 1992). Depending on the ratio of starch to protein, gel formation and properties may differ, with e.g. higher protein content in starch-protein composite gels being associated with augmented pasting temperature and reduced gel firmness (Bravo-Núñez, Garzón, Rosell, & Gómez, 2019;Joshi, Aldred, Panozzo, Kasapis, & Adhikari, 2014;Núñez-Santiago, Bello-Pérez, & Tecante, 2004;Oñate Narciso & Brennan, 2018;Onwulata et al., 2014;Ribotta, Colombo, León, & Añón, 2007;Yang et al., 2004). According to Eliasson (1983), higher protein content alters the water retention capacity of the system because the proteins compete with starch for available water, thereby causing an increase in pasting temperature. ...
... According to Eliasson (1983), higher protein content alters the water retention capacity of the system because the proteins compete with starch for available water, thereby causing an increase in pasting temperature. Protein adsorption to granule surfaces during pasting could explain both the reduced pasting viscosity and increased pasting temperature, as the adsorbed proteins would restrict water diffusion and thus reduce and delay granule swelling Oñate Narciso & Brennan, 2018). Joshi et al. (2014) found that the pasting temperature increased from 73.5 • C in 100% starch systems to 82.4 • C in 50:50 lentil starch/lentil protein systems, and attributed this to the characteristically high denaturation temperature (118 • C) of lentil protein isolate. ...
... Breakdown viscosity has also been found to be lower for starchprotein mixtures compared to that of the corresponding sample containing only starch (Oñate Narciso & Brennan, 2018;Onwulata et al., 2014). In a study adding 10% extra protein, breakdown of starch-protein mixed pastes was no longer detected, suggesting that the protein gel network increased the resistance to mechanical shearing (Joshi et al., 2014). ...
... Because of the undesired processing materials that remain after chemical modification and the high price of enzymatic modification, recently, the tendency to use physical modification as a green and cheap method has increased [7,8]. Moreover, the incorporation of other food-derived ingredients such as proteins [9][10][11][12], polyphenols [13], and polysaccharides [6,14] to starch in order to improve its physicochemical properties has received much attention in recent years. Proteins can improve the structural, textural, thermal, and pasting properties of food products through multiple interactions with other biopolymers, especially starch [15,16]. ...
... Moreover, the highest WAC was observed by adding 8% of MBPI to NCS, with a value of 10.92 g/g. Similar results were reported for adding soy protein concentrate to barley starch-lentil protein concentrate blends [9]. In contrast, Sun and Xiong [34] observed reducing SP and WAC of pea starch by blending it with pea protein isolate. ...
... Additionally, Du et al. [31] reported that the WAC of MBPI was higher than that of fenugreek protein concentrates and soy protein isolate. The hydrophobic amino acids could reduce the WAC of starch-protein composite by covering the surface of starch granule and inhibiting the starch swelling [9,37]. However, the hydrophilic groups and amino acids could form crosslink bonds with water and/or starch and promote starch swelling [19]. ...
Starch is widely used in food and non-food industries because of its unique characteristics. However, native starch shows some weaknesses that restrict its applications. Recently, some studies have demonstrated the benefits of using protein to overcome these limitations. Therefore, the aim of the present study was to investigate the effect of mung bean protein isolate (MBPI) (2%, 4%, 6%, and 8%) on the physicochemical, pasting, and thermal properties of native corn starch (NCS), as a novel starch–protein composite. Higher swelling power (SP), water absorbance capacity (WAC), and solubility values of NCS were observed with increasing MBPI concentration. Additionally, by the addition of MBPI, the rapid visco analyzer (RVA) showed a reduction in pasting temperature (77.98 to 76.53 °C), final viscosity (5762 to 4875 cP), and setback (3063 to 2400 cP), while the peak viscosity (4691 to 5648 cP) and breakdown (1992 to 3173 cP) increased. The thermal properties of NCS/MBPI gels investigated by differential scanning calorimetry (DSC) showed higher onset, peak, and conclusion temperatures (69.69 to 72.21 °C, 73.45 to 76.72 °C, and 77.75 to 82.26 °C, respectively), but lower gelatinization enthalpy (10.85 to 8.79 J/g) by increasing MBPI concentration. Fourier transform infrared spectroscopy (FT-IR) indicated that the addition of MBPI decreased the amount of hydrogen bonds within starch. Furthermore, after three cycles of freeze-thaw shocks, the syneresis of NCS-MBPI composites decreased from 38.18 to 22.01%. These results indicated that the MBPI could improve the physicochemical properties of NCS, especially its syneresis and retrogradation characteristics.
... The pasting properties of rice starch with different BSSF contents are shown in Fig. 1 and Table 1. Peak viscosity (PV) is related to the swelling capacity of rice starch, and it is affected by the friction and water absorption competition between leached amylose and ungelatinised granules (Narciso & Brennan, 2018). Final viscosity (FV) reflects the thickening ability of rice starch, and it is remarkably influenced by the movement of water molecules around the amylose and amylopectin. ...
... Thus, BSSFs could reduce the viscoelastic properties of gelatinised rice starch. Previous studies have confirmed that the addition of cellulose gum decreased the G 0 and G″ of wheat starch , revealing that DF interfered with the gelatinisation among amylose chains (Narciso & Brennan, 2018). Ahmad & Williams (2001) demonstrated that a starch Figure 1 Pasting property curves of rice starch with bamboo shoot shell fibres (BSSFs) at different contents (BSSFs/rice starch = 0%, 1%, 2%, 5% and 10%, w/w). ...
... Several discernible absorptions at 1156 and 1080 cm À1 were attributed to the stretching vibration of C-O, C-C and C-O-C antisymmetric stretching vibration . Moreover, the absorption peaks at 933 and 763 cm À1 proved the existence of a-1,6-Dglycosidic and a-1,4-D-glycosidic bonds (Narciso & Brennan, 2018). ...
The effects of different bamboo shoot shell fibre (BSSF) content (1, 2, 5 and 10%, w/w) on the physical, thermal and structural properties of rice starch were investigated. BSSFs significantly affected the properties of rice starch by competitive water absorption and hydrogen bonding. With increased BSSF content, the breakdown value and pasting temperature of rice starch were increased, whereas the peak viscosity, final viscosity and setback value were decreased. Thermodynamic results showed that the gelatinisation temperature and gelatinisation enthalpy of rice starch were significantly increased by the 5% and 10% BSSFs. Furthermore, BSSFs interconnected with amylose through hydrogen bonds to restrain gel‐structure formation, thereby resulting in low storage modulus and loss modulus of rice starch paste. A loose structure of rice starch supplemented with 10% BSSFs was clearly visible, exhibiting the minimum values of hardness (32.12 ± 4.47 g) and adhesiveness (64.70 ± 17.32 g). Moreover, BSSFs increased the amount of short‐range ordered structures but had no effect on the crystal type of rice starch. These results may contribute to the manufacture and development of fibre‐enriched starchy products.
... In particular, it has been reported that the starch gelatinization seems to be inhibited with increasing protein concentration, as shown by a delayed onset temperature of gelatinization and a reduced viscosity/hardness of the final gel. In addition, researchers have also suggested that the presence of amylose may affect the rheological properties, reporting that 20% pea protein isolate (PPI) substitution in a mixture containing waxy rice starch reduced the peak and final viscosity to a lesser extent than when rice starch contained amylose (Oñate Narciso & Brennan, 2018). Nonetheless, substituting the starch with protein will reduce the actual concentration of starch in the mix, modifying the volume occupied by the starch granules during swelling, and, then, the effect of protein on starch granular swelling will be difficult to evaluate. ...
... This delayed starch gelatinization transition has also been observed in potato protein/starch mixes, and has been attributed to the competition for water between the two polymers (Lu et al., 2016). Other authors have proposed that the delay of starch swelling and gelatinization may also be related to protein adsorption to the starch granule surface (Kett et al., 2013;Noisuwan, Hemar, Wilkinson, & Bronlund, 2011;Oñate Narciso & Brennan, 2018), either via hydrogen bonding between protein and starch or via hydrophobic or hydrophilic interactions between exogenous proteins and starch-bound proteins on the granules (Noisuwan et al., 2011). In this regard, it is worth noting that HAMS presented a higher content of endogenous bound proteins (0.5%) than NMS (0.3%) and WMS (0.2%), measured and reported in materials section. ...
... Right after food enters the digestive system, the amylose and amylopectin [71] components of starch could hinder the digestion of other proteins [72]. The fortification of basmati rice starch, containing 20-25% amylose, with pea protein resulted in a diminished protein digestibility when compared with a glutinous starch containing only 0-3% amylose. ...
... This decrease was associated with the integration of the proteins into the amylose network that was formed after the leaching of amylose. Accordingly, the low amylose type of starch promotes the formation of a less extensive amylose network that increases the digestibility of proteins [72]. Interestingly, the pea protein-based meat substitutes exhibited higher protein digestibility when the amylose content was increased [73]. ...
Cereal products are regarded as important protein providers, though they could feature poor nutritional quality due to their occasional imbalanced amino acid content. Cereal proteins are low in cysteine or tryptophan, and rich in methionine; however, while their combination with legume proteins makes them nutritionally more comprehensive, such a possibility must be addressed by the cereal processing industry. However, the incorporation of legume protein concentrates and isolates might also influence the functionality and bioavailability of some cereal constituents. Therefore, the objective of the present review is to gain insights into the effects of cereal products incorporated with legume protein isolates/concentrates, knowing that both the cereals and the protein extracts/isolates are complex structural matrices, and besides the final products acceptability they should efficiently promote the health condition of consumers. The combination of legume proteins with cereals will bring about a structural complexity that must harmoniously include proteins, carbohydrates, lipids, polyphenols and dietary fibers to promote the bioaccessibility, bioavailability and bioactivity without cyto- and genotoxicity.
... These crosslinks may be responsible for their higher batter viscosity compared with the batter with only starch [31]. In addition, the high molecular weight proteins had a great propensity to form crosslinks with WS [32]. The molecular weights of SP were a magnitude higher than those of EP and WP [33][34][35]. ...
... The result may be explained because SP, EP, and WP reinforced the heat stability of crust, thereby delaying moisture evaporation. Among the four types of crust, the moisture loss of the SP crust was the slowest, which is attributed to the high moisture absorption capacity and molecular weight [31,32]. With continuing heating, depolymerization and decomposition of high-molecular weight proteins and WS will occur [51,52], resulting in the loss of WS and protein gel weight. ...
Soy protein (SP), egg white protein (EP), and whey protein (WP) at 6% w/w were individually incorporated into the batter of a wheat starch (WS) and wheat gluten (WG) blend (11:1 w/w ratio). Moisture adsorption isotherms of WS and proteins and the viscosity, rheological behavior, and calorimetric properties of the batters were measured. Batter-breaded fish nuggets (BBFNs) were fried at 170 °C for 40 s followed by 190 °C for 30 s, and pick-up of BBFNs, thermogravimetric properties of crust, and fat absorption were determined. The moisture absorption capacity was the greatest for WS, followed by WG, SP, EP, and WP. The addition of SP significantly increased the viscosity and shear moduli (G″, G′) of batter and pick-up of BBFNs, while EP and WP exerted the opposite effect (p < 0.05). SP, EP, and WP raised WS gelatinization and protein denaturation temperatures and crust thermogravimetry temperature, but decreased enthalpy change (ΔH) and oily characteristics of fried BBFNs. These results indicate that hydrophilicity and hydration activity of the added proteins and their interactions with batter matrix starch and gluten reinforced the batter and the thermal stability of crust, thereby inhibiting fat absorption of the BBFNs during deep-fat frying.
... Studies have shown that addition of pea protein to cereal products improved the nutritional values of these products by providing the essential amino acid profile, meanwhile, the texture and structure were also affected at various degrees F I G U R E 2 The flow chart of plant protein-based material prepared meat analogue through high-moisture extrusion. Information from Liu and Hsieh (2008) and Chen, Wei, and Zhang (2011) (Bustillos, Jonchere, Garnier, Reguerre, & Valle, 2020;Morales-Polanco, Campos-Vega, Gaytan-Martinez, Enriquez, & Loarca-Pina, 2017;Narciso, & Brennan, 2018;Song & Yoo, 2017;Wee, Loud, Tan, & Forde, 2019). Compared to commercial crackers using wheat flour as a principal ingredient, the cracker prepared by dehulled oat and pea protein exhibited lower hardness (19.04 N) and gumminess (4.07 N) and higher values of cohesiveness (0.35), springiness (0.45 mm), and chewiness (0.35) (Morales-Polanco et al., 2017). ...
... In addition, the ricesubstituted noodle with added PPI and GTE not only exhibited better cooking and viscoelasticity properties, but also had higher antioxidant activity (Song & Yoo, 2017). The study of Narciso and Brennan (2018) indicated that in PPI-fortified rice starch products, pea protein could be effectively digested without causing a significant increase in blood glucose levels. Although addition of native or denatured PPI did not affect obviously product texture and sensory perceptual characteristics of wheat noodles, the noodle with added denatured PPI had a reduction in in vitro glucose release (Wee et al., 2019). ...
In recent years, the development and application of plant proteins have drawn increasing scientific and industrial interests. Pea (Pisum sativum L.) is an important source of high‐quality vegetable protein in the human diet. Its protein components are generally considered hypoallergenic, and many studies have highlighted the health benefits associated with the consumption of pea protein. Pea protein and its hydrolysates (pea protein hydrolysates [PPH]) possess health benefits such as antioxidant, antihypertensive, and modulating intestinal bacteria activities, as well as various functional properties, including solubility, water‐ and oil‐holding capacities, and emulsifying, foaming, and gelling properties. However, the application of pea protein in the food system is limited due to its poor functional performances. Several frequently applied modification methods, including physical, chemical, enzymatic, and combined treatments, have been used for pea protein to improve its functional properties and expand its food applications. To date, different applications of pea protein in the food system have been extensively studied, for example, encapsulation for bioactive ingredients, edible films, extruded products and substitution for cereal flours, fats, and animal proteins. This article reviews the current status of the knowledge regarding pea protein, focusing on its health benefits, functional properties, and structural modifications, and comprehensively summarizes its potential applications in the food industry.
... Numerous studies have focused on investigating the interactions of proteins of animal and plant origin with starches [4][5][6]. Extensive research about starch protein interactions has been conducted with regard to processing e.g. through extrusion, cooking, dough formation, soaking and mixing [7]. Combining starch and protein results in stronger gels with better mechanical and textural properties due to a synergistic effect when the components are structurally compatible [8,9]. ...
Proteins can significantly improve the elasticity and microstructure of starch gels in food. In this work, the influence
of chickpea protein flour on the viscoelastic behaviour of carboxymethylated starch (CMS, 92.6 mmol
COOH kg 1) gels was studied as function of pH and temperature. A weight ratio CMS:protein flour of 1:0.45 was
investigated in the pH range of pH 2.5–8. Above pH 7 presence of 7.5 %w/w chickpea flour lead to an increase in
complex viscosity of a 16.5 %w/w CMS solution by a factor of 10. The interaction between CMS and protein
above pH 4 accelerates gelation at 37 ◦C, resulting in an increase in viscosity by a factor of 5, 10 and 120 at pH 5,
pH 7 and pH 8 respectively. Model calculations for species dissociation of ammonium groups in basic amino acids
and carboxylate groups in CMS indicate that electrostatic interactions led to the observed increase in viscosity.
The results form a general model to explain the pH-dependent viscoelastic behaviour of polysaccharide–protein
mixtures. The understanding of the mechanism of action between protein and polysaccharides is a condition for
targeted analysis and explanation of many phenomena of texture, stability and coacervate formation in food
processing.
... WPr is considered a complete protein as it is composed of all the nine EAAs in adequate quantities for optimal physiological function [40]. Even though PPr also contains all the nine EAAs, it has been considered incomplete due to an inadequate quantity of methionine [41]. Despite the differences between the PPr and WPr amino acid composition, the findings of the current study demonstrated comparable benefits of PPr and WPr supplementation for individual muscle strength and mass. ...
Animal-sourced whey protein (WPr) is the most popular protein supplement among consumers and has been shown to improve muscle mass and strength. However, due to allergies, dietary restrictions/personal choices, and growing demand, alternative protein sources are warranted. Sedentary adults were randomized to pea protein (PPr) or WPr in combination with a weekly resistance training program for 84 days. Changes in whole-body muscle strength (WBMS) including handgrip, lower body, and upper body strength, body composition, and product perception were assessed. The safety outcomes included adverse events, vital signs, clinical chemistry, and hematology. There were no significant differences in the change in WBMS, muscle mass, or product perception and likability scores between the PPr and WPr groups. The participants supplemented with PPr had a 16.1% improvement in WBMS following 84 days of supplementation (p = 0.01), while those taking WPr had an improvement of 11.1% (p = 0.06). Both study products were safe and well-tolerated in the enrolled population. Eighty-four days of PPr supplementation resulted in improvements in strength and muscle mass comparable to WPr when combined with a resistance training program in a population of healthy sedentary adults. PPr may be considered as a viable alternative to animal-sourced WPr without sacrificing muscular gains and product enjoyment.
... Proteins are efficient plasticisers that influence the rearrangement of starch amylose and decrease the viscosity of starch solutions due to diminished retrogradation of amylose chains during cooling (Narciso and Brennan 2018). ...
This study aimed to produce spray dried acerola juice microparticles with different protein carriers to be incorporated into edible starch films. The microparticles were evaluated for solids recovery, polyphenol retention, solubility, hygroscopicity, particle size distribution, X-ray diffraction, phytochemical compounds and antioxidant activity. Acerola microparticles produced with WPI/hydrolysed collagen carriers (AWC) with higher solids recovery (53.5 ± 0.34% w/w), polyphenol retention (74.4 ± 0.44% w/w), high solubility in water (85.2 ± 0.4% w/w), total polyphenol content (128.45 ± 2.44 mg GAE/g) and good storage stability were selected to produce starch-based films by casting. As a result, cassava films with water vapour permeability of 0.29 ± 0.07 g mm/m2 h KPa, polyphenol content of 10.15 ± 0.22 mg GAE/g film and DPPH radical scavenging activity of 6.57 ± 0.13 μM TE/g film, with greater migration of polyphenol to water (6.30 ± 0.52 mg GAE/g film) were obtained. Our results show that the incorporation of phytochemical-rich fruit microparticles is a promising strategy to create biodegradable edible films.
... The viscosity of GPS/CA and GPS/WP was much larger than that of CA and WP because of the effect of hydrated PS. The high viscosity of GPS hindered the movement of MP and prevented the accession of enzymes to digest MP [42]. For the ternary system, the protein digestibility of GPS/CA/SBO and GPS/WP/SBO was lower than that of GPS/CA and GPS/WP, respectively. ...
The in vitro digestibility of potato starch-based foods interacting with milk protein and soybean oil was investigated. Microstructures and rheological changes upon digestion were determined. The results showed that the addition of milk proteins (casein and whey protein) promoted gelatinized potato starch digestion, while soybean oil slowed down gelatinized potato starch digestion. A mixture of soybean oil and milk protein promoted the digestion of milk protein, while a mixture of gelatinized potato starch and milk protein inhibited the digestion of milk protein. The mixture of milk protein and/or gelatinized potato starch with soybean oil promoted the release of free fatty acids in soybean oil. The highest release rate of free fatty acids was attained by a mix of milk protein and soybean oil. The mixed samples were digested and observed with a confocal laser scanning microscope. The viscosity of the digestates was determined by a rheometer. Overall, the results demonstrated that the addition of milk protein and soybean oil had an effect on the in vitro digestibility of gelatinized potato starch and its microstructure.
... Furthermore, extruded rice products (ERPs) such as rice noodles do not contain gluten, lack cohesion and extensibility, and their texture is also poor (Ojukwu et al., 2020). However, the consumption of legumes being rich in lysine and grains can play a perfect complementary role in humans, it also may affect the GI and resistant starch (RS) content of rice (Oñate Narciso & Brennan, 2018;. Thus to improve the quality of rice noodles and reduce the GI of starch-based foods, it is imperative to add whole legumes flour or its components to ERPs. ...
In recent years, legumes have become increasingly popular because of their high nutritional value and health benefits. Moreover, most legumes have a low glycaemic index (GI) and are often considered in dietary interventions for diabetes. Extruded rice products (ERPs) are trendy in major rice‐producing areas, including staple foods (such as rice noodles) and snack foods (such as rice cake). However, ERPs have a higher GI and a relatively simple nutritional composition. Therefore, adding whole legumes flour or its components to ERPs is a significant issue, which can reduce ERPs' GI and improve these products' nutritional value. This paper reviewed the nutritional properties and physiological functions of legumes flour or its components. In addition, the factors (starch and extrusion processing) affecting the quality and GI of ERPs were summarised. Besides, this paper reviewed after adding whole legumes flour or its components to ERPs, the products' appearance and quality are better and its nutritional properties are also better, especially with regard to type 2 diabetes mellitus (T2DM). Moreover, this review also summarised three‐dimensional (3D) printing technology in ERPs could improve the products' quality and nutritional value. Finally, directions that will be the focus of 3D printing and legumes were highlighted.
... Существует множество исследований, в которых сообщается, что добавление горохового белка в зерновые продукты может повысить пищевую ценность продукта, поскольку гороховый белок обеспечивает незаменимые аминокислоты и улучшает текстуру зернового продукта [36][37][38][39][40]. Растительный белок может использоваться в качестве заменителя животного белка для удовлетворения пищевых потребностей лакто-вегетарианцев и, таким образом, может сделать пищу более здоровой. ...
Vegetable peas are by far the most widely used among the main vegetable legumes. Due to its high nutritional value, it has an important food value and is cultivated almost everywhere. High nutritional qualities of vegetable peas are determined by the content of protein, carbohydrates, dietary fiber, vitamins, as well as macro– and microelements. Pea protein is popular due to its affordable price compared to animal protein. The value of pea protein is determined by its amino acid composition and its high balance, especially valuable amino acids that are not synthesized in animals and humans.The article discusses the nutritional value of vegetable peas (green beans; fresh, frozen and canned vegetable peas; dry seeds); the content of water-soluble protein, amino acid composition, the content of macro- and microelements in the seeds of vegetable peas of FSBSI FSVC selection varieties; the quality of green peas as raw materials for canning, depending on the type of seeds and the structure of starch grains; requirements for the quality of raw vegetable peas for canning; seedlings and microgreens as useful and nutritious products for fresh consumption; medicinal properties of vegetable peas; varieties of vegetable peas for various uses.
... Previous studies have shown that higher soluble protein had greater influence on the gelatinization properties of starch [16]. It is also indicated that small molecular weight proteins had a stronger effect on the inhibition of starch retrogradation or digestibility than large molecular weight proteins [17,18]. ...
Modification of plant-based protein for promoting wide applications is of interest to the food industry. Rice protein from rice residues was modified by homogenization, and its effect on pasting properties (including gelatinization and rheology) of rice starch was investigated. The results showed that homogenization could significantly decrease the particle size of rice protein and increase their water holding capacity without changing their band distribution in SDS-PAGE. With the addition of protein/homogenized proteins into rice starch decreased peak viscosity of paste. The homogenized proteins decreased breakdown and setback value when compared with that of original protein, indicating homogenized protein might have potential applications for increasing the stability and inhibiting short-term retrogradation of starch paste. The addition of protein/homogenized proteins resulted in a reduction in the viscoelasticity behavior of starch paste. These results indicate that homogenization would create a solution to alter the physicochemical properties of plant proteins, and the homogenized proteins may be a potential candidate for development of protein-rich starchy products.
... Oñate Narciso and Brennan [114] found a relationship between the amylose content of starch with protein digestion. Pea PI was combined with starch from basmati and glutinous rice, with high and low amylose to amylopectin ratios, respectively. ...
Plant protein concentrates and isolates are used to produce alternatives to meat, dairy and eggs. Fractionation of ingredients and subsequent processing into food products modify the techno-functional and nutritional properties of proteins. The differences in composition and structure of plant proteins, in addition to the wide range of processing steps and conditions, can have ambivalent effects on protein digestibility. The objective of this review is to assess the current knowledge on the effect of processing of plant protein-rich ingredients on their digestibility. We obtained data on various fractionation conditions and processing after fractionation, including enzymatic hydrolysis, alkaline treatment, heating, high pressure, fermentation, complexation, extrusion, gelation, as well as oxidation and interactions with starch or fibre. We provide an overview of the effect of some processing steps for protein-rich ingredients from different crops, such as soybean, yellow pea, and lentil, among others. Some studies explored the effect of processing on the presence of antinutritional factors. A certain degree, and type, of processing can improve protein digestibility, while more extensive processing can be detrimental. We argue that processing, protein bioavailability and the digestibility of plant-based foods must be addressed in combination to truly improve the sustainability of the current food system.
... However, swelling of the starch granules was restricted in presence of protein. The difference in molecular weight (MW) of proteins present in PI from different rice types on starch swelling and gelatinisation may not be ruled out, since the adsorption of protein vary with MW (Ryan & Brewer, 2007;Narciso & Brennan, 2018). ...
The amino acids composition, protein profiling and functional properties of protein isolates from different pigmented rice (PR), nonpigmented rice (NPR) and improved rice (IR) varieties were determined and their effects of incorporation on starch thermal, and dynamic rheological were evaluated to know the possible interactions in food matrix. Protein isolates (PI) from PR and IR showed better foaming capacity and, foam stability than those from NPR. PI from both the PR and IR showed higher proportion of histidine, threonine, valine, methionine, phenylalanine and isoleucine. PI from IR showed higher accumulations of glutelins (31 and 33kDa, 21 and 22 kDa) and prolamins (15kDa, 16kDa, 17 kDa and 20kDa) than those from rice types. Starches from IR showed higher storage modulus (Gʹ) and loss modulus (Gʺ) than that from PR, and NPR, and decreased on addition of PI. PI from PB1121 IR was more suitable for protein enrichment due to more lightness value, and superior functionality (emulsification and foaming properties). Starch‐protein interaction affects the functionality, and behaviour of matrix and, developing hypoallergenic infant formulations or other food products.
... The findings may be applied in formulating and processing protein-fortified nutrition formula in which the whey protein and oat starch interactions and coacervations determine phase stability and textural nature of processed foods. Previous research found both whey protein and vegan proteins may affect the recrystallization of starch molecules during retrogradation, consequently affecting the content of resistant starch (or the starch digestibility) in the heat-treated starch gel systems (Lu et al., 2016;Oñate Narciso and Brennan, 2018). This study may be considered the first step to understand the WPI effects on oat starch to better develop whey protein-fortified oat-based food products with possibly reduced starch digestibility. ...
We investigated the effects of different concentrations of whey protein isolate (WPI) on oat starch characteristics in terms of pasting, thermal, and structural properties. The pasting properties of the starch showed that hot paste viscosity increased with the addition of WPI in the system, and relative breakdown decreased. Thermal analysis showed a significant effect of WPI on oat starch by increasing the peak temperature of differential scanning calorimeter endotherms. The X-ray diffraction and Fourier transform infrared spectroscopy studies revealed that WPI increased the ordered structuration of starch paste, as evident by an increase in relative crystallinity; in addition, a decrease in infrared bands at 1,024 cm⁻¹ and 1,080 cm⁻¹ suggested decreased gelatinization of oat starch granules. Overall, WPI at different concentrations affected the oat starch gelatinization properties.
... 17 Starch is also abundant in rice. 18 Starch is considered one of the best natural polymers due to its abundance, renewability, costeffectiveness and biodegradability. [19][20][21] However, starch biopolymers are dissolvable in water and have low mechanical strength, which has proved to be a major negative aspect. ...
The present study focuses on testing the potential of starch from two different sources: corn and rice, to produce bioplastics, and the impact of natural agricultural waste materials (eggshells and rice hulls) as fillers. Bioplastic samples with different starches, plasticizers and amounts of fillers, in varying combinations, were prepared to determine the feasibility of the produced bioplastics. The physico-chemical properties of the bioplastics, such as moisture content, water absorption, water and alcohol solubility, biodegradability, tensile strength and Young’s modulus, were investigated. FT-IR analysis was also performed. The RTV silicone coating of the samples was tested to induce hydrophobic properties to water-soluble bioplastics. This study demonstrated that the utilization of starches from different sources, various types of plasticizers, as well as filler types and amounts, can have a significant impact on the physico-chemical properties of the bioplastics. Moreover, the bioplastics produced are safe for the environment and biodegradable, so starch-based bioplastics can be a promising environmentally friendly alternative to harmful petroleum-based plastics.
... In other research, whey protein surrounded or encapsulated the starch granules and acted as a physical barrier towards the digestibility of the starch in the WPI and starch blends prepared by cooking in a boiling water bath for 20 min [17]. Furthermore, Narciso and Brennan [18] showed that whey protein concentrate reduced the peak, breakdown and final viscosities of rice starch without significantly increasing the content of released glucose. However, in these WPI and starch composite systems, the digestibility of the starch was more focused on the intestinal step of the simulated digestion rather than on the gastric step. ...
The exogenous protein (e.g. whey protein isolate, WPI) is commonly used to fortify and modify the functionality of starchy food, that might influence starch hydrolysis during gastric digestion. In this study, the effect of whey protein on the digestion of lotus seed starch (LS) subjected to a dynamic in vitro gastric digestion was investigated. The particle size distribution, the swelling power of the starch and the changes in pH, viscosity, microstructure and hydrolysis of 2% LS and blends of 2% LS with 1, 2 and 4% WPI were investigated. The presence of whey protein caused decreases in the particle size and the swelling power and an increase in the viscosity of the LS granules. The presence of whey protein also delayed the decrease in the pH and increased the hydrolysis of LS during the in vitro gastric digestion. WPI surrounded or encapsulated the LS granules observed using confocal laser scanning microscopy, and may have been the reason for the decrease in swelling power of the starch granules. The increased degree of gastric digestion of LS with the addition of WPI was largely related to the delayed decrease in the gastric pH rather than to alterations in the swelling power and viscosity and WPI’s physical barrier toward starch.
... Apart from the gluten network and the viscoelastic properties of the dough, changes in the viscosity of the formulations during heating also influenced bread quality. As a general trend, replacement of BF with more fibrous ingredients resulted in a reduction in peak viscosities, likely due to the reduction in the overall starch content, as well as the increase in competition for hydration by the fibre and protein fraction of BSG and FBSG [47,56,57]. Both ingredient type (p < 0.006) and addition level (p < 0.001) influenced the evaluated pasting parameters. ...
Recycling of by-products from the food industry has become a central part of research to help create a more sustainable future. Brewers’ spent grain is one of the main side-streams of the brewing industry, rich in protein and fibre. Its inclusion in bread, however, has been challenging and requires additional processing. Fermentation represents a promising tool to elevate ingredient functionality and improve bread quality. Wheat bread was fortified with spray-dried brewers’ spent grain (BSG) and fermented brewers’ spent grain (FBSG) at two addition levels to achieve “source of fibre” and “high in fibre” claims according to EU regulations. The impact of BSG and FBSG on bread dough, final bread quality and nutritional value was investigated and compared to baker’s flour (BF) and wholemeal flour (WMF) breads. The inclusion of BSG and FBSG resulted in a stronger and faster gluten development; reduced starch pasting capacity; and increased dough resistance/stiffness. However, fermentation improved bread characteristics resulting in increased specific volume, reduced crumb hardness and restricted microbial growth rate over time. Additionally, the inclusion of FBSG slowed the release in reducing sugars over time during in vitro starch digestion. Thus, fermentation of BSG can ameliorate bread techno-functional properties and improve nutritional quality of breads.
... There are many studies which report that by the addition of pea protein in cereal products can improve the nutritional value of the product because pea protein provides the essential amino acids and improve the texture of cereal product [4,[82][83][84][85]. The plant protein can be used as substitute for animal protein for meeting nutritional need of lacto-vegetarians and thus can make the food healthier. ...
Grain legumes are well known as staple sources of soluble protein worldwide. Pea is essentially the most quickly growing crop for immediate human consumption and has the potential for higher effect as being a protein supply for foods processing apps. Pea seeds are an essential source of plant-based proteins. The better acceptance of pea protein-rich food is due to pea manifold attributes, excellent functional qualities, high vitamin value, accessibility, and comparatively small cost. Pea proteins are not merely nutritional amino acids but are an indispensable source of bioactive peptides that offer health benefits. This chapter focuses on the present information of isolation methods, extraction, and of seed proteins in pea. Overall, we believe that analogous research and advancement on pea proteins would be required for further more substantial increase in pea protein utilization is envisaged.
... The ranges of peak viscosity (PV) and breakdown viscosity (BD) were from 1373.67 cP to 811.67 and 148.67 to 83.33 cP. The inclusion of bran into flour decreased PV and BD values and indicated that the sample mixture with greater bran had more resistance to heat and was difficult to [28,29]. The final viscosity (FV) ranged from 1286.67 to 2562.00 cP, and this decreased as the proportion of buckwheat bran increased, with 15% buckwheat bran having the lowest viscosity. ...
This study investigated the effects of different levels of buckwheat bran inclusion onto the physicochemical, pasting properties and in vitro starch digestibility of buckwheat flour gels. Total phenolic content and antioxidant activities (DPPH radical-scavenging activity and ferric reducing/antioxidant power) were also measured. Total starch content per 100 g of gel ranged from 64.45 to 75.66, and the percentage of resistant starch ranged from 1.36% to 1.75%, while protein ranged from 12.07% to 12.93%. The results showed that the amount of bran addition decreased total starch and slightly reduced protein content, but increased resistant starch content. The level of bran addition increased the total phenolic content and antioxidant activity of the gels, while it reduced the blood sugar response. As the bran levels increased, the glucose released decreased (95.17, 84.08, 69.80, 60.23 mg glucose/g sample, respectively). The results showed that the bran of buckwheat (a pseudocereal) has nutritional value and can be used in the development of buckwheat products.
... Meanwhile, protein crosslinks could be observed after cooking. Interestingly, foxtail millet proteins always surrounded the native or swollen starch granules, whether cooking or not (Fig. 4A1, B1), which was consistent with the protein distributions in a starch-protein-water mixture during rice cooking (Narciso and Brennan, 2018). Such a relative position of starch and protein in the endosperm suggested a protein barrier effect of foxtail millet during cooking. ...
Protein-protein crosslinks, especially disulfide bonds, widely exist and influence the quality of cereal-based food. In order to investigate the effect of disulfide bonds on pasting properties of foxtail millet, ten typical varieties were selected and separated into three groups according to their eating quality, and then reducing agent dithiothreitol (DTT) was used to disrupt disulfide bonds. Disulfide and sulfhydryl groups’ variations, pasting, and hydration properties were determined. Scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) were also used to analyze the microstructure of foxtail millet paste. Results showed that foxtail millet with poor eating quality was more prone to form disulfide bond linkage at a higher rate and degree during cooking. Disrupting disulfide bonds increased peak viscosity, breakdown, water absorption, and swelling power of granules. Meanwhile, pasting temperature, setback, and final viscosity decreased significantly. The larger size of swollen starch granules and breakage of protein networks were found under CLSM, and firmer lamellar structures with less connections and pores were illustrated under SEM in DTT-treated paste. After DTT-treatment, disulfide bonds were believed to restrict hydration and pasting properties of foxtail millet, and strengthen the swollen granules and paste rigidity as well as a high level of starch reassociation.
... In recent years, due to increased attention in relation to exogenous protein fortification, glycemic index reduction and functionality modification of starchy foods, studies that have investigated the blending of starch and whey protein have become increasingly important. These studies have predominantly focused on the interactions between starch and whey proteins under the simple blend and their effects on the rheological, pasting, thermal, gelling, microstructural, and digestion properties of the blend system (Kumar, Brennan, Mason, Zheng, & Brennan, 2017;Lavoisier & Aguilera, 2019;Narciso & Brennan, 2018;Ren & Wang, 2019). However, up until now, to the best of our knowledge no study has been performed to investigate the effect of dry heating on the properties of starch in the presence of whey protein. ...
The effect of dry heating treatment with whey protein isolate (WPI) on the morphological and physicochemical properties of rice starch (RS) was investigated. Scanning electron microscopy results demonstrated that WPI-mediated aggregation of RS granules was more pronounced as the dry heating time increased, which was further confirmed by analysis of the particle size distribution. Differential scanning calorimetry results showed that dry heating treatment in the presence of WPI significantly decreased the gelatinization temperature of RS but without affecting the gelatinization enthalpy change. X-ray diffraction and Fourier transform infrared spectroscopy analysis demonstrated that the long and short range orders of RS were partially damaged following dry heating treatment and the incorporation of WPI. In addition, a significant increase in the oil-binding ability was observed in the dry heated starch samples, which was more pronounced under the combination of dry heating with WPI. These phenomena could be attributed to the interaction of RS with WPI, the aggregation and denaturation of WPI, and the disruption of hydrogen bonds within starch during the treatment process.
This study was designed to investigate the morphological, structural, rheological, functional, and emulsifying properties of native (NKS) and octenyl succinic anhydride (OSA)-esterified Kodo millet starch (EKS) blended with commercial pea protein (PP), soy protein (SP), and whey protein (WP). The effects of esterification and blending on the stabilization of oil-in-water Pickering emulsions were also evaluated. Morphological analysis revealed significant starch‒protein interactions, causing deformation and surface irregularities in the NKS and EKS blends, with stronger interactions in the esterified blends due to hydrophilic and hydrophobic forces. Structural characterization revealed similar crystalline structures in starch‒protein blends, with increased X-ray diffraction peaks after protein addition. However, esterification reduced the pasting temperature (PT) from 88.80°C (NKS) to 83.25°C (EKS), and protein addition further decreased the PT by 0.5–4.80% for the NKS blends and 0.25–1.62% for the EKS blends, indicating reduced swelling resistance and thermal stability. Rheological tests of starch‒protein blend suspensions revealed shear-thinning flow and elastic-dominant (G'>G'') behavior, with EKS‒protein blends exhibiting stronger gel networks. NKS-protein blends had relatively high water absorption capacities (2.37–2.43 g/g), whereas EKS-protein blends showed higher oil absorption capacities (2.32–2.37 g/g). The emulsifying activity index (11.03 to 12.76–16.21) and emulsifying stability index (70.49 min to 93.85–99.62 min) increased after blending, with Pickering emulsions remaining stable for a minimum of two weeks. However, emulsion stability was highest for the EKS-SP blends, which remained stable for up to 25 days. Overall, the esterification of starch increased its compatibility with proteins, leading to improved emulsifying properties and more stable emulsions.
Starch is the principal source of stored energy in plants, and its chemical composition varies depending on the botanical source of the starch. There are several different sources of starch, including conventional and non-conventional sources. The conventional sources of starch comprise cereal grains; tubers; roots; the pith of the sago plant; and legumes, mainly peas. However, there is a great demand for novel sources of starch to obtain other or new functional properties and to ensure the production sustainability of starch. The novel sources of starch comprise mango, jackfruit, litchi, longan, loquat, and banana. Starch has several different applications in the food industry and non-food sectors, including pharmaceutical and cosmetic applications. In the food industry, starch can be used as a thickening and binding agent in the preparation of pudding, soups, sauces, salad dressings, mayonnaise, and infant foods. The use of starch in different applications depends on its functional properties, where gelatinization and rheological characteristics are the main functional and physicochemical properties of starch to define its applications in different industries. This chapter covers the chemical composition and structure of starch granules, with an emphasis on their physicochemical properties, such as swelling and solubility, gelatinization and retrogradation, pasting and rheological properties, and digestibility. It also focuses on starch functionality, its applications in different sectors, and the different methods for starch isolation.
Background and Objectives
Starch modification using heat‐moisture treatment (HMT) has been proven to influence starch functionality and nutritional properties as it can increase resistant starch content and reduce the glycemic index (GI). This study aims to determine the nutritional and functional properties of infrared (IR)‐ and microwave (MW) heat‐moisture‐treated (HMT) white and red non‐tannin, and red tannin sorghum meals with the aim of further reducing the estimated GI.
Findings
All treated meals had significantly ( p < .05) lower pasting peak viscosity than the untreated samples, possibly due to aggregate formation observed under the light microscope, restricting the starch from swelling to form a high‐viscosity paste. There was a decrease in the percentage of starch hydrolysis between the sorghum types and a further decrease after HMT treatment. A significant difference was observed in the protein digestibility between the sorghum types, but not between the treatments.
Conclusion
HMT with IR and MW further reduced the starch digestibility, possibly because of changes in the starch molecular configuration.
Significance and Novelty
This study suggests that the changes in the starch functionality and nutritional properties of the HMT‐treated sorghum meals can potentially be useful in the development of lower‐GI sorghum foods. The results also differentiate the characteristics of sorghum types.
Wheat protein hydrolysates (WPH) were prepared by pepsin hydrolysis for 30, 60, and 120 min (WPH30, WPH60, and WPH120). The mixed system of rice starch and WPH was hydrothermally treated to explore the effect of WPH with different degrees of hydrolysis on starch digestion. WPH reduced the first-order rate coefficient (k) of starch digestion. Especially, WPH30 reduced the k value the most and formed the highest slowly digestible starch content due to the entanglement of starch chains and long-chain peptides. WPH60 and WPH120 with more hydrophobic peptides and polar amino acids than WPH30 tended to form hydrogen bonds with starch molecules due to less steric hindrance. Particularly, the complexation of WPH60 promoted the formation of dense aggregate structure and hindered the enzymatic hydrolysis of starch to a certain extent, thereby increasing the resistant starch content. These findings provide significant guidance for the preparation of hypoglycemic reformed food.
Background
Starch and proteins are found in many flour-based food products, and they provide the energy and nutrients the human body needs. The interactions between them often significantly affect the structure and properties of starch. Studying the interactions of protein and its hydrolysates with starch under different processing conditions and the mechanisms by which they affect the digestive properties of starch can provide a theoretical basis for the design and production of starch-based food products with good nutritional functions.
Scope and approach
In vivo or in vitro, proteins can be hydrolyzed by acid, base, or protease. During hydrolysis, proteins are broken down into peptides with small molecular weights and finally hydrolyzed into amino acids. This study aims to review the effects of endogenous or exogenous proteins in food and their hydrolysates (peptides and amino acids) on the structure, properties, and digestibility of starch, and the interactions of starch with proteins or protein hydrolysates under specific processing conditions. On this basis, we consulted relevant literature and summarized the reasons for the influence of protein and its hydrolysates on starch digestibility.
Key findings and conclusions
Proteins and protein hydrolysates (peptides and amino acids) have different effects on the microstructure, crystal structure, chemical structure, and thermal stability of starch under different conditions. In addition, protein and its hydrolysates can regulate the digestive properties of starch and can be used as ingredients for low-glycemic starch-based food.
Exogenous proteins in starchy foods may alter the digestibility of the starch. In this study, the effect of whey protein isolate (WPI) with different ratios on the digestibility of co-gelatinized corn starch (CS) was studied, and the possible mechanisms were investigated. The rapidly digestible starch (RDS) content was reduced from 66.89% to 59.01% and the resistant starch (RS) content was increased from 14.47% to 22.78% when 4.5% WPI was added during co-gelatinization. This exogenous protein also suppressed the reduction of the average molecular weight of starch during digestion. WPI had no effect on CS digestibility when starch and protein were gelatinized separately and mixed during digestion. The inhibition of starch digestion by WPI was closely related to the protein-starch interaction. Rheological property analysis indicated strong hydrogen bonding interactions were formed between WPI and CS during co-gelatinization. The physical barrier of WPI also had a certain inhibitory effect on the digestion of starch, while WPI only had a transient effect on the viscosity of the digestive juice. Meanwhile, WPI restricted the hydrolysis of CS by inhibiting the activities of α-amylase and amyloglucosidase, and the inhibition of amyloglucosidase activity had a special effect on the rapid digestion of starch at the early stage.
Background
Starches and proteins are two major types of biopolymer components, especially in many flour (starch)-based foods consumed worldwide, which provide energy and nutrition needed by the human body. In many such starch-based matrices (the main structural component of such foods), proteins and their interactions with starches greatly influence the matrix structure and properties. Studying the different roles played by proteins (endogenous and exogenous) in various starch-based food systems can provide a frame of reference for the design and production of improved starch-based food products with tailored properties and desirable nutritional functions.
Scope and approach
Significant efforts have recently been made to tailor the morphology, structure, and properties of many starch-based food systems, and thus to design various starch-based food products with satisfactory attributes. This review surveys the latest literature on starch-based matrices containing proteins. Discussed are the influences of proteins and their interactions with starches on the morphologies and structures (e.g. short- and long-range orders) of starch-based matrices, as well as on their pasting, thermal, rheological, textural, sensory, and digestive properties. Also, current understandings of structure–property links are presented, along with their implications on the production of various starchy foods (e.g. pastas, breads, cakes, and biscuits), including gluten-free versions.
Key findings and conclusions
Proteins in many starchy food matrices can encapsulate the starch phase (or be adsorbed on its surfaces) on a micron scale, and thereby interact with starch chains via both non-covalent (e.g. hydrogen bonding, hydrophobic, and electrostatic) and covalent bonds (e.g. via Maillard reactions). These facts and protein features (e.g. hydration and gelation abilities) can play major roles in inhibiting starch retrogradation (the reassembly of cooked starch chains into ordered structures) and in regulating various other properties of such starch-based matrices, including viscosity, transition temperatures, moduli, hardness, sensory, digestibility, and shelf-life. Despite the fact that the current literature presents considerable information on the structure–property relationships of many different starch-based matrices and their applications in the processing of various starchy foods (e.g. pastas, noodles, and biscuits), it is still highly necessary to define more comprehensive correlations among starch–protein interactions, starch-protein matrix structures, and the resulting properties of such food products.
BACKGROUND
The amino acid composition, and rheological, thermal and colloidal stability of plant protein‐based oil‐in‐water emulsion systems containing 1.90, 3.50 and 7.70 g 100 mL⁻¹ protein, fat and carbohydrate, respectively, using quinoa and lentil protein ratios of 100:0 and 60:40 were investigated. The emulsion containing lentil protein showed lower initial, peak and final viscosity values (22.7, 61.7 and 61.6 mPa s, respectively) than the emulsion formulated with quinoa protein alone (34.3, 102 and 80.0 mPa s, respectively) on heat treatment.
RESULTS
Particle size analysis showed that both samples had small particle sizes (~1.36 μm) after homogenization; however, the sample with 60:40 quinoa:lentil protein ratio showed greater physical stability, likely related to the superior emulsifying properties of lentil protein. However, upon heat treatment, large aggregates (~100 μm) were formed in both samples, reducing the physical stability of the samples. This physical stability was increased with the addition of 0.20% sodium dodecyl sulfate (SDS), whereas it was negatively affected by the addition of α‐amylase. Addition of α‐amylase led to lower viscosity for both emulsion samples, with measured values of 41.8 and 46.0 mPa s for the 100:0 and 60:40 samples, respectively. This suggests that the heat‐induced increases in particle size were partially due to hydrophobic interactions between the proteins as SDS disrupts hydrophobic bonds between proteins.
CONCLUSION
These results demonstrated that using a mixture of lentil and quinoa proteins positively affected the physical stability of plant protein‐based emulsions, in addition to contributing to a more nutritionally complete amino acid profile – both important considerations in the development of plant‐based beverages. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
The aim of this study was to evaluate the effect of potato protein (PP) on thermal and rheological characteristics of maize starches with different amylose contents. Samples were prepared by substituting 0, 1, 2 or 3 parts by weight of PP for 10 parts by weight of high amylose (HA), common (CM) or waxy (WM) maize starch. The PP had a different influence on the thermodynamic gelatinization characteristics of starch. Gelatinization enthalpy of the CM and WM starches increased from 12.08 to 21.76 J/g and from 16.95 to 25.62 J/g, respectively, when the highest amount of the PP was used. Pasting temperature of the HA and CM starches decreased by 0.3–1.56 °C and 0.43–3.60 °C, respectively, while that of WM starch remained unchanged. The HA starch‐PP pastes showed higher final viscosity (736 × 10–3–2123 × 10–3 Pa⋅s) than the starch‐only paste (580 × 10–3 Pa⋅s). The starch‐protein pastes exhibited a shear‐thinning flow and a phenomenon of thixotropy. Substitution of the part of the HA or CM starch with the PP resulted in weakened viscoelastic structures of the produced gels, while the WM starch gel structure has been strengthened. Results of our study may be useful in designing maize starch‐based foods supplemented with potato protein.
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This study evaluates the proximate composition, amylose, resistant starch, pasting properties, total phenolic content (TPC), antioxidant capacities, and amino acid profiles of banana flour and cassava flour in comparison to semolina flour. Banana flour and cassava flour have a lower protein content (4.54% and 1.41%) but higher total dietary fiber (16.46% and 10.99%) than semolina flour (12.36% and 7.07%, respectively). The two gluten‐free flours have a lower amylopectin content compared to semolina flour. Banana flour shows high nutritional qualities (resistant starch, TPC, and antioxidant capacities) compared to cassava and semolina flours. The amino acid evaluation shows that banana and cassava flours have a better ratio of total essential amino acid to total amino acid (35.37% and 29.95% vs 23.34%) but have lower limiting essential amino acid values (0.98% and 1.51% vs 11.12%) than semolina flour. Understanding the different physicochemical, functional, and nutritional properties of banana and cassava flours helps to inform the development of gluten‐free cereal products based on these flours. Physicochemical, pasting properties and nutritional qualities of banana flour and cassava flour are investigated alongside semolina flour. The two gluten‐free flours have varied physicochemical, functional, and nutritional property characteristics compared to semolina flour and show great potential to be utilized in the development of gluten‐free cereal products.
Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate‐rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co‐ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.
Present trends towards technologies and processes that increase the use of
residues make starchy vegetal biomass an important alternative material in
various applications due to starch’s versatility, low cost and ease of use when
its physicochemical properties are altered. Starch is increasingly used in many
industrial applications and as a renewable energy resource. Starch can be
modified to enhance its positive attributes and eliminate deficiencies in its
native characteristics. In this article, the state of knowledge on conventional
and unconventional starches and their properties, characteristics, modifications
and applications are reviewed.
Rice is an important staple food for more than half of the world's population. Especially in Asian countries, rice is a major contributor to dietary glycaemic load (GL). Sustained consumption of higher-GL diets has been implicated in the development of chronic diseases such as type 2 diabetes mellitus. Given that a reduction in postprandial glycaemic and insulinaemic responses is generally seen as a beneficial dietary change, it is useful to determine the variation in the range of postprandial glucose (PPG) and insulin (PPI) responses to rice and the primary intrinsic and processing factors known to affect such responses. Therefore, we identified relevant original research articles on glycaemic response to rice through a systematic search of the literature in Scopus, Medline and SciFinder databases up to July 2014. Based on a glucose reference value of 100, the observed glycaemic index values for rice varieties ranged from 48 to 93, while the insulinaemic index ranged from 39 to 95. There are three main factors that appear to explain most of the variation in glycaemic and insulinaemic responses to rice: (1) inherent starch characteristics (amylose:amylopectin ratio and rice cultivar); (2) post-harvest processing (particularly parboiling); (3) consumer processing (cooking, storage and reheating). The milling process shows a clear effect when compared at identical cooking times, with brown rice always producing a lower PPG and PPI response than white rice. However, at longer cooking times normally used for the preparation of brown rice, smaller and inconsistent differences are observed between brown and white rice.
The paste viscosity of starches Amioca (~0.5% amylose), native corn (~27% amylose), Hylon VII (~70% amylose), tapioca (~19% amylose), and their whey protein isolate (WPI; 50/50) mixtures at varying solid concentration of 2.5, 5, 10, 15 and 20% were determined. At higher gel concentration (20%) during the cooling cycle, WPI paste measured by rapid visco-analyser (RVA) showed a tremendous increase in viscosity over that of the micro visco-amylograph (MVA), 5784 and 184 cP, respectively. RVA gels had a more uniform network of coarse particles (~250—500 nm) than the fine structures (~50 nm) in those of the MVA. Inclusion of WPI reduced the paste viscosity of all starches by at least 50%, except for Hylon VII at 20% solid concentration. The strength of Hylon VII and corn starch gels was reduced by WPI. In contrast, gels of WPI/tapioca (G' = 45.4 Pa) and WPI/amioca (G' = 18.3 Pa) had similar rheological properties as their pure starch control (G' = 47.4 Pa and G' = 15.3 Pa for Tapioca and Amioca, respectively).
Milk and milk products are nutritious food items containing numerous essential nutrients, but in the western societies the consumption of milk has decreased partly due to claimed negative health effects. The content of oleic acid, conjugated linoleic acid, omega-3 fatty acids, short- and medium chain fatty acids, vitamins, minerals and bioactive compounds may promote positive health effects. Full-fat milk has been shown to increase the mean gastric emptying time compared to half-skimmed milk, thereby increasing the gastrointestinal transit time. Also the low pH in fermented milk may delay the gastric emptying. Hence, it may be suggested that ingesting full-fat milk or fermented milk might be favourable for glycaemic (and appetite?) regulation. For some persons milk proteins, fat and milk sugar may be of health concern. The interaction between carbohydrates (both natural milk sugar and added sugar) and protein in milk exposed to heat may give products, whose effects on health should be further studied, and the increasing use of sweetened milk products should be questioned. The concentration in milk of several nutrients can be manipulated through feeding regimes. There is no evidence that moderate intake of milk fat gives increased risk of diseases.
The inability of humans and many farm animals to synthesize certain amino acids has long triggered tre- mendous interest in increasing the levels of these so- called essential amino acids in crop plants. Knowledge obtained from basic genetic and genetic engineering research has also been successfully used to enrich the content of some of these essential amino acids in crop plants. Among the essential amino acids, Lys, Trp, and Met have received the most attention because they are most limiting in cereals (particularly Lys and Trp) and legumes crops (particularly Met), which represent the major sources of human food and animal feed world- wide. Enriching crop plants in essential amino acids has both economical and humanitarian interest. In developed countries, the interest is mostly for the livestock feeding industry because farm animals gen- erally provide sufficient amount of essential amino acids for human diets. In developing countries, where plants directly account for the majority of the food, the interest is both humanitarian and economical. So far, the success of genetic approaches has been mostly restricted to maize (Zea mays) by generating quality protein maize (QPM) cultivars, which are enriched in Lys and to some extent Trp in their seeds. However, genetic approaches have resulted in rela- tively limited success in other crop species. This is mostly due to limited availability of genetic resources for plant breeding, and the fact that genetic traits for high contents of Lys, Trp, or Met are generally associ- ated with abnormal plant growth because these traits do not operate in a seed-specific manner. In contrast, results from genetic engineering research appear to be more promising, particularly because this approach allows seed-specific expression of specific traits of interest, using seed-specific promoters. In fact, one high-Lys maize cultivar, LY038, developed by genetic engineering, represents the first genetically modified (GM) crop with high nutritional value to be approved for commercial use in a number of countries. The potential to increase the contents of Trp and Met in a seed-specific manner have already been proven suc- cessful in basic research studies. Another advantage of genetically engineered traits is that they can be trans- formed into multiple plant species and genotypes and function synergistically with many other agro- nomically important traits. These genetic engineering approaches were generally aimed at tailor-made im- provements of essential amino acid metabolic path- waysandexpressingnativeandgeneticallyengineered proteins enriched in essential amino acid contents. However, improvements of metabolic pathways by genetic engineering also requires a detailed under- standing of how these pathways interact with regula- tory networks that fine tune plant development. These are nowbeginning tobe elucidatedbymodernsystems biology approaches, including transcriptomics, proteo- mics, and metabolomics. Due to space limitation, we focus this review only on approaches that have been extensively studiedand provensuitable toimprovethe nutritional quality of food and feed. We also only cover research associated with nutritional improvements for monogastric mammals, namely, human and certain farm animals, particularly poultry and swine. These approachesarenotasimportantforruminantlivestock, such as beef, because these animals require the pres- ence of the essential amino acids in proteins that are resistant to rumen proteolysis. Approaches suitable for ruminant animals are discussed in the following re-
This study aimed to understand effects of adding corn oil (CO) and soy protein (SP) to corn starch on the physicochemical properties and digestive rates of annealed starch complex and mechanisms of interactions between corn starch (CS), CO and SP. Binary and ternary blends were prepared using CS mixed with CO (10%, dsb) and/or SP (10%, dsb) and incubated in a water bath at 50 °C for 14 h. Results showed that more agglomerates of the granules were in the ternary blends. With the addition of CO and/or SP, the CS displayed a decreased pasting temperature, an increased peak viscosity and a decreased enthalpy change of amylose-lipid complex dissociation. The CO can reinforce but SP hinder the annealing phenomenon. Results also showed that CO decreased retrogradation of CS, whereas SP increased it. The digestibility studies showed that the addition of CO and SP decreased the content of rapidly digestible starch and increased the sum of slowly digestible starch and resistant starch contents. SP displayed more impact on the digestibility of the ternary blends than CO. The physical barrier of CO, and amylose-lipid complex and protein-starch matrix can provide resistance to starch digestion.
The rate of enzymic digestion of the three major macronutrients (protein, triglyceride and starch) in the human diet has a controlling influence on physiological and hormonal responses underpinning many of the risk factors for major non-communicable diseases. Previously, the interactions among macronutrients and the inter-dependence of individual macronutrient enzymic hydrolysis processes have been largely ignored. We now report a comprehensive study of component interactions in the enzymic hydrolysis of starch, protein and lipids representing both gastric and small intestinal digestion using wheat flour as an exemplar. Enzymic susceptibility of individual macronutrients in wheat flour was affected by each of a range of interactions among constituents as well as interactions of enzymes with non-substrate macronutrients. The results show the importance of food structure in attenuating the rate and extent of hydrolysis of starch, protein, and lipids, and highlight the fact that studies performed on isolated macronutrient/enzyme systems may not represent the complexities of real digestion.
Starch retrogradation is a process in which disaggregated amylose and amylopectin chains in a gelatinized starch paste reassociate to form more ordered structures. Starch retrogradation has been the subject of intensive research over the last 50 years, mainly due to its detrimental effect on the sensory and storage qualities of many starchy foods. However, starch retrogadation is desirable for some starchy food products in terms of textural and nutritional properties. To better understand the effect of starch retrogradation on the quality of starchy foods, measurement methods of starch retrogradation and factors that influence starch retrogradation have been studied extensively. This article provides a comprehensive review of starch retrogradation including the definition of the process, molecular mechanisms of how it occurs, and measurement methods and factors that influence starch retrogradation. The review also discusses the effect of retrogradation on the in vitro enzyme digestibility of starch. Spectroscopic methods such as FTIR and Raman are considered to be very promising in characterizing starch retrogradation at a molecular level, although more studies are needed in the future.
With an annual production of more than two billion tons cereals are amongst the most important commodities in the world. Thus, products made from cereals are staple foods that contribute considerably to the energy and nutrient intake of mankind. The major cereals are corn, wheat, rice, barley, sorghum, millet, oats, and rye. Their constituents affect the nutritional and technological properties of cereals. Carbohydrates are the main constituents with starch providing energy and texture. However, although nonstarch polysaccharides are minor constituents they represent dietary fiber and exhibit positive health effects, in particular for whole grain products. Cereal proteins are quantitatively less important than carbohydrates, but they are of major importance for the functional properties, in particular for the bread-making performance of wheat and rye or for the quality of tortillas made from corn. The protein composition of different cereals varies considerably, but they have in common that lysine and methionine contents are low. Thus, cereal proteins are of poor nutritional value. Lipids are a minor constituent of cereals, but particularly in wheat flour polar lipids positively affect dough properties and enable the production of bread with good texture and quality. Whole grain cereals are important sources of minerals and B-vitamins.
The use of aged milled rice with an intermediate amylose content (20–25%) in the preparation of fermented rice cake yielded a steamed cake with a greater volume and an optimum softness as compared with similar cakes prepared from rice with a lower or higher amylose content. Aging of the rice decreased gas (CO2) retention during fermentation, but improved gas retention and cake volume during steaming.
Pasta is traditionally manufactured using only durum wheat semolina, but it is possible to incorporate other flours or ingredients into pasta in order to increase its nutritional value to the consumer, compared to conventional pasta. For this reason, pasta was prepared substituting durum wheat semolina with 15% of enriched dietary fibre flours (Glucagel, inulin Raftiline® HPX, inulin Raftiline® GR, psyllium and oat). Moreover, all dietary fibres (excluded Glucagel) were added in combination in order to evaluate their possible antagonistic or synergic effect on predicted glycaemic response. In general, all enriched dietary fibre pasta sample showed a significant decrease (except for pasta containing a combination of 7.5% inulin Raftiline® GR and 7.5% oat bran flour) in reducing sugars released and standardised AUC values compared to control pasta. However, this study showed that the combination of dietary fibres in pasta formulation led to an antagonistic effect on the predicted glycaemic response.
Rice is the staple food for over half the world's population. Approximately 480 million metric tons of milled rice is produced annually. China and India alone account for ∼50% of the rice grown and consumed. Rice provides up to 50% of the dietary caloric supply for millions living in poverty in Asia and is, therefore, critical for food security. It is becoming an important food staple in both Latin America and Africa. Record increases in rice production have been observed since the start of the Green Revolution. However, rice remains one of the most protected food commodities in world trade. Rice is a poor source of vitamins and minerals, and losses occur during the milling process. Populations that subsist on rice are at high risk of vitamin and mineral deficiency. Improved technologies to fortify rice have the potential to address these deficiencies and their associated adverse health effects. With the rice industry consolidating in many countries, there are opportunities to fortify a significant share of rice for distribution or for use in government safety net programs that target those most in need, especially women and children. Multisectoral approaches are needed for the promotion and implementation of rice fortification in countries.
Seven experimental oat lines with high (6.2-7.2%), medium (5.5-5.9%), and low (4.4-5.3%) β-glucan concentrations were evaluated for contributions of β-glucan, starch, protein, and their interactions, to pasting properties of oat flours by using a Rapid Visco Analyser (RVA, Newport Scientific, Warriewood, NSW, Australia). Significant correlations (P < 0.05) between β-glucan concentration and pasting parameters of oat slurries were obtained under autolysis without 1 h of incubation, inhibition, and amylolysis. The relative decrease of viscosity after enzymatic hydrolysis of β-glucan correlated with β-glucan concentration (P < 0.05). These data demonstrated the important contribution of β-glucan to pasting. The relative decrease of viscosity after either amylolysis or enzymatic removal of protein correlated with β-glucan concentration (P < 0.1), which might be explained by the considerable contribution of the interaction of β-glucan with starch and protein, to pasting. The viscosity decrease by hydrolysis of protein was much greater than the actual viscosity remaining after hydrolysis of both β-glucan and starch, reconfirming the importance of interactions between protein and other oat components to pasting. Optimal multiple linear regression (MLR) models were generated to predict key pasting parameters in both buffer without 1 h of incubation and silver nitrate solution by using a stepwise procedure. The β-glucan concentration alone or together with the concentration of starch, rather than protein, was selected as the predictor under certain conditions. These results illustrated the major unit contribution of β-glucan, secondary unit contribution of starch, and minimal unit contribution of protein to pasting.
Humans, as well as farm animals, cannot synthesize a number of essential amino acids, which are critical for their survival. Hence, these organisms must obtain these essential amino acids from their diets. Cereal and legume crops, which represent the major food and feed sources for humans and livestock worldwide, possess limiting levels of some of these essential amino acids, particularly Lys and Met. Extensive efforts were made to fortify crop plants with these essential amino acids using traditional breeding and mutagenesis. However, aside from some results obtained with maize, none of these approaches was successful. Therefore, additional efforts using genetic engineering approaches concentrated on increasing the synthesis and reducing the catabolism of these essential amino acids and also on the expression of recombinant proteins enriched in them. In the present review, we discuss the basic biological aspects associated with the synthesis and accumulation of these amino acids in plants and also describe recent developments associated with the fortification of crop plants with essential amino acids by genetic engineering approaches.
The interactions between starch and proteins during processing influence pasting and rheological properties of starch and produce modifications on starch gel structure. Enzymatic modifications have been proposed for overcoming the limitations of using proteins as food ingredients. This work aimed to study the impact of native and enzymatically modified pea proteins on the properties of protein-starch (from cassava or corn) gels. Pea protein isolate (PPI) was incubated with endopeptidase (AL) or microbial transglutaminase (TG). Pasting profile, rheological behaviour and water retention capacity of protein-starch gels were analyzed. Protein (native and enzymatically modified) incorporation increased the viscosity of both corn and cassava starches during gel preparation. However, the hydrolyzed protein reduced drastically the increment of viscosity of protein-starch gels. The addition of PPI led to corn starch network that shifted from an elastic-like nature to a more viscous-like, whereas the opposite effect was observed in cassava gel network. TG- and AL-treated proteins led to a decrease of both G′ and G′′ moduli of protein-starch gels, and AL-treated proteins showed the highest decrease on these parameters. Hydrolyzed proteins also favoured the syneresis of the protein-corn starch gel, whereas crosslinked proteins tended to reduce it. Enzymatic modifications of pea proteins affected significantly pasting and rheological properties of protein-starch gels. All rights reserved, Elsevier.
The adsorption of sodium caseinate (NaCAS) and whey protein isolate (WPI) to both normal and waxy rice starch granules was investigated using SDS-PAGE. This showed that the proteins present in NaCAS and WPI do adsorb to normal and waxy rice starch granules and that in the case of NaCAS, for both normal and waxy rice starch, αs-casein adsorbed preferentially and in higher amounts than β-casein. In the case of WPI, although the amount of adsorbed β-LG is higher than that of α-LAC, no preferential adsorption is observed. Confocal laser scanning microscopy, with specific dyes, was also used in an attempt to locate the milk proteins adsorbed to the starch granules. The adsorption isotherms of these two milk protein ingredients to rice starch granules, were modelled using the BET equation which is usually used to model multilayer adsorption, and a simple equation is proposed to take into account possible absorption of the proteins into the core of the starch granules. Good agreement is found between these models and the experimental results. Possible mechanisms involved in the interaction between milk proteins and starch granules are discussed.
Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (To), peak (Tp) and conclusion (Tc) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA-viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated.
Alkaline protease digestion with a food-grade enzyme was used to produce rice starch from wet-milled rice flour (WMRF). In a 3×3 factorial modelling experiment, recoveries of starch and levels of protein contamination were determined at pH 8·5–10·0, protease levels of 0·5–1·5% (based on WMRF), and digestion times of 5·0–30·0 h. The following digestion conditions were kept constant; 55 °C with mild agitation, 34–37% (w/v) flour solids, and alkalinity to within ±0·2 pH units. Regression equations with the three variables explained 92% and 98%, respectively, of the variances in starch recovery and protein contamination. Upon digestion with 1·1% protease at pH 10·0 and 18·0 h, starch recovery was 95% and protein contamination was 0·5%. Most hydrolysis of rice protein occurred in the first 3–4 h of digestion as determined by the consumption of sodium hydroxide (NaOH). Rice starch also was isolated by extraction of WMRF with c. 2·5 parts of 0·05 NaOH at c. pH 12. The recovery of starch was c. 10% higher with the protease method than with the NaOH method, and the effluents contained mostly amino acid salts as opposed to protein mixed with alkali. The rice starch isolated by protease digestion was lighter in appearance, contained more lipid, and gave a somewhat lower consistency after pasting. The raw materials used to isolate rice starch by the protease method were approximately twice as costly in 1996 as those in the NaOH method, principally because of the cost of the protease (55% of total).
The objective of this study was to evaluate the association between heat and pressure-treated soy proteins and wheat prime starch relative to the level of granule surface proteins present. Soy isolates were manufactured from defatted soy flour and from two types of textured soy flour. Conditions for binding between wheat starch and soy fractions were established by altering pH, protein and sucrose concentrations. Conformations of exogenous proteins bound to the wheat starch granule surface were evaluated using an amyloglucosidase assay. Proteins present on the granule surface were removed and soy protein binding was reevaluated. Thermal and pressure processing of soy protein significantly influenced binding kinetics. Textured soy proteins exhibited increased wheat starch granule adsorption characteristics compared to untreated soy protein. Removal of native wheat starch granule surface proteins decreased the binding of added proteins. This suggests that native granule proteins may mediate the binding of exogenous protein.
Gelatinisation and retrogradation of starch-whey mixtures were studied in water (pH 7) using the Rapid Visco-Analyser (RVA). The starch:whey ratios ranged from 0:100 - 100:0. Wheat starch, and whey protein concentrate (about 80% solids basis) and isolate (about 96% solids basis) were used. Mixtures with whey isolates were generally more viscous than those with whey concentrates, and this was attributed to fewer non-protein milk components in the former. Whey protein concentrates and isolates reduced the peak, trough and final viscosities of the mixtures, but the breakdown and setback ratios of the mixtures were increased. The gelatinisation temperature increased with whey substitutions indicating that whey protein delayed starch gelatinisation. The temperature of fastest viscosity development decreased as the amount of whey was increased. Whey protein isolate generally exercised a lesser effect than the concentrate. At between 40 - 50% whey substitutions, the dominant phase changed from starch to protein irrespective of the source of the whey protein. An additive law poorly defined selected RVA parameters. Both macromolecules interacted to define the viscosity of the mixture, and an exponential model predicted the viscosity better than the additive law. The results obtained in this study are discussed to assist the understanding of extrusion processing of starch-whey systems as models for whey-fortified snack and ready-to-eat foods.
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