Article

Yogurt: The Product and its Manufacture

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Abstract

Even if yogurt is one of the oldest fermented dairy products, it remains very popular today because of its image as ‘modern’ fermented food, resulting from its attractive nutritional properties and its increasing diversification, associated with the industrialization of its manufacture. After a short definition of yogurt and fermented milks, the microbiological characteristics and the main biochemical mechanisms involved in their manufacture are presented. The three main steps of the manufacturing process, that is, the mix preparation, fermentation, and harvesting/packaging, are then developed. Finally, the main microbiological, physicochemical, and sensory analyses and controls of the yogurts' quality are summarized.

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... bulgaricus grows as ovoid cells. They convert lactose into galactose that is not metabolized and glucose that is fermented predominantly to lactic acid, thus corresponding to homofermentative metabolism (Corrieu & Béal, 2015). ...
... pH, viscosity, and Brix of the added fruits. Acidification Acidification activity of starter cultures is also assessed, mostly by using the Cinac system that allows determining various quantitative kinetic descriptors (Corrieu & Béal, 2015). ...
... They refer mainly to the control of temperature (in fermentation tanks, heat exchangers, incubation rooms, and cooling systems), pH (by sampling either in the fermentation tanks or directly in cups), and duration of the different steps of manufacture. In addition to these controls, the use of food safety management systems such as ISO 22000 or International Food Standards is requested to control foodborne safety hazards and guarantee the products" safety (Corrieu & Béal, 2015). ...
Presentation
Yogurt is a semisolid fermented product made from a standardized milk mix by the activity of a symbiotic blend of Streptococcus salavarius subsp. thermophilus and Lactobacillus delbruechii subsp. bulgaricus cultures. For the sake of brevity we shall term the yogurt culture organisms as ST and LB. Milk of various mammals is used for making yogurt in various parts of the world. However, most of the industrialized production of yogurt uses cow's milk. It is common to boost the solids-not-fat fraction of the milk to about 12% with added nonfat dry milk or condensed skim milk. The increased protein content in the mix results in a custard like consistency following the fermentation period (Hui, 1992). The typical composition and nutrient profile of yogurt are shown in Table below. In general, yogurt contains more protein, calcium, and other nutrients than milk, reflecting extra solids-not-fat content.
... bulgaricus grows as ovoid cells. They convert lactose into galactose that is not metabolized and glucose that is fermented predominantly to lactic acid, thus corresponding to homofermentative metabolism (Corrieu & Béal, 2015). ...
... pH, viscosity, and Brix of the added fruits. Acidification Acidification activity of starter cultures is also assessed, mostly by using the Cinac system that allows determining various quantitative kinetic descriptors (Corrieu & Béal, 2015). ...
... They refer mainly to the control of temperature (in fermentation tanks, heat exchangers, incubation rooms, and cooling systems), pH (by sampling either in the fermentation tanks or directly in cups), and duration of the different steps of manufacture. In addition to these controls, the use of food safety management systems such as ISO 22000 or International Food Standards is requested to control foodborne safety hazards and guarantee the products" safety (Corrieu & Béal, 2015). ...
... lactis etc. are also not uncommon in some countries (Mckinley, 2005). The use of these traditional cultures has some advantages that it can grow even at low pH and their growth is not affected by acidity (Aswal et al., 2012;Corrieu and Beal, 2016;Mbaeyi-Nwaoha et al., 2017). Our literature search showed that pH, titratable acidity, syneresis and sensory profiles of yoghurt samples from the Kingdom of Lesotho have not been reported previously. ...
... However, among these volatile compounds, acetaldehyde is the major flavour compound of yoghurt which gives pleasant, fresh and fruity aroma. The low flavour values could be due to the high content of carbohydrate which increases the sweetness of yoghurt (Ndife et al., 2014;Corrieu and Beal, 2016). ...
... Y 1 received the lowest score of 2.2 and this may be attributed mainly due to its high viscosity. The panellists appreciated the increased viscosity as it makes yoghurt chewable before swallowing (Corrieu and Beal, 2016). Even though appearance, texture and thickness are very important characteristics to contribute the quality of yoghurt, the flavour is generally considered as the most important of all and critical indicator of consumer acceptability (Olugbuyiro and Oseh, 2011). ...
Article
A total of nine yoghurt samples purchased from the Kingdom of Lesotho were evaluated for their pH, titratable acidity, syneresis and sensory profiles following standard procedures. The pH, titratable acidity and syneresis of these nine samples were found to be in the range of 3.94-4.22, 0.69-1.81 and 1.76-35.15%, respectively. The sensory profiles such as appearance, texture, aroma, flavour, taste and overall acceptability of these nine samples were found to be in the range of 2.5-4.5, 2.2-3.3, 2.5-4.1, 1.7-4.0, 2.1-4.3 and 2.3- 3.9, respectively. The pH of all nine yoghurt samples was complying in accordance with FDA specifications. The percentages of titratable acidity of some yoghurt samples were complying in accordance with FDA specifications and some samples were not. On the other hand, some samples have remarkably high syneresis. Our study showed that the pH, titratable acidity, syneresis and sensory profiles of these yoghurt samples were significantly different (p<0.05). Sensory properties, particularly, flavour, taste and aroma of yoghurt samples are needed to be improved for a better consumer overall acceptability. To the best of our knowledge, this is the first report of this kind on yoghurt samples from the Kingdom of Lesotho.
... bulgaricus grows as ovoid cells. They convert lactose into galactose that is not metabolized and glucose that is fermented predominantly to lactic acid, thus corresponding to homofermentative metabolism (Corrieu & Béal, 2015). ...
... pH, viscosity, and Brix of the added fruits. Acidification Acidification activity of starter cultures is also assessed, mostly by using the Cinac system that allows determining various quantitative kinetic descriptors (Corrieu & Béal, 2015). ...
... They refer mainly to the control of temperature (in fermentation tanks, heat exchangers, incubation rooms, and cooling systems), pH (by sampling either in the fermentation tanks or directly in cups), and duration of the different steps of manufacture. In addition to these controls, the use of food safety management systems such as ISO 22000 or International Food Standards is requested to control foodborne safety hazards and guarantee the products" safety (Corrieu & Béal, 2015). ...
Presentation
Full-text available
Yogurt is a semisolid fermented product made from a standardized milk mix by the activity of a symbiotic blend of Streptococcus salavarius subsp. thermophilus and Lactobacillus delbruechii subsp. bulgaricus cultures. For the sake of brevity we shall term the yogurt culture organisms as ST and LB. Milk of various mammals is used for making yogurt in various parts of the world. However, most of the industrialized production of yogurt uses cow's milk. It is common to boost the solids-not-fat fraction of the milk to about 12% with added nonfat dry milk or condensed skim milk. The increased protein content in the mix results in a custard like consistency following the fermentation period (Hui, 1992). The typical composition and nutrient profile of yogurt are shown in Table below. In general, yogurt contains more protein, calcium, and other nutrients than milk, reflecting extra solids-not-fat content. Today, yoghurt remains a milk-based fermented milk that is presented to the consumer in either a gel form (set yoghurt) or as a viscous fluid (stirred yoghurt) but, as figures for consumption have risen, so manufacturers have expanded the market by introducing an ever wider range of fruit flavours and/or changing the image of the product, e.g. by raising the total solids and fat contents of a standard stirred yoghurt to give a product with a luxury image. Nevertheless, despite these and other innovations, the method of manufacture is still based on the system employed by nomadic herdsmen many centuries ago. For example, the majority of yoghurts consumed worldwide are manufactured with cultures of bacteria with growth optima of 37–45ºC, and this characteristic derives from the fact that the species in question, namely Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, evolved in the Middle East where the ambient temperature in the summer months is often well in excess of 35ºC. Similarly, the universal method of manufacturing a satisfactory yoghurt is based on the traditional process expanded (Tamime, 2006).
... bulgaricus. This fermentation leads to acidification and milk coagulation (Corrieu and Béal, 2016). In many populations across the globe, yoghurt is known for its health-promoting attributions such as improvment of both lactose absorption and lactose intolerance reduction, the antimicrobial activity, the amelioration of protein and lipid digestibility, and the immune system stimulation (Jeantet et al., 2008). ...
... In many populations across the globe, yoghurt is known for its health-promoting attributions such as improvment of both lactose absorption and lactose intolerance reduction, the antimicrobial activity, the amelioration of protein and lipid digestibility, and the immune system stimulation (Jeantet et al., 2008). These gains have allowed the industrial production of yoghurt and fermented milks to grow exponentially, causing a huge demand and important profits as shown in the reported statics: about 32-35 million tons in 2012, for an expected global market in 2015 of about $67 billion (Corrieu and Béal, 2016). This growth of the global dairy market is attributed mainly to the advent of functional foods (Baglio, 2014). ...
Article
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Consumers are focusing more and more on health benefits of functional products. The aim of this work is to formulate and characterize novel functional powder obtained by freeze-drying yoghurt supplemented concomitantly with pomegranate peel powder (0–10%) and honey (0–5%). In order to examine the powdered yoghurt, it was subjected to measurements of physicochemical, physical, microbiological and antioxidant properties. The experimental data of freeze-drying were fitted to four models and results showed that Page model was the most suitable thin-layer drying model according to R² and RMSE as statistical comparison indexes. There was no significant difference (p > 0.05) among the powder samples in terms of moisture content and flow properties. The bulk and tapped densities values of yoghurt samples were slightly affected (p < 0.05) by the addition of pomegranate peel and honey. The results also demonstrated that powders particles exhibit an amorphous structure with mean diameter (D4.3) values that varied from 106.68 to 143.37 μm. Moreover, the addition of pomegranate peel and honey increased the glass transition temperature (Tg) value of yoghurt powder, and this could improve its stability during storage. Total lactic acid bacteria in all yoghurt powders remained over 10⁷ cfu/g of dry matter after the freeze-drying. All the fortified yoghurt displayed higher phenolic contents and, consequently, exhibited higher antioxidant activities than control powder sample. It is concluded that, the freeze-drying of yoghurt with pomegranate peel and honey, at the fortification levels tested, is feasible, and the obtained powder has acceptable physicochemical and physical properties which could improve its shelf-life. Thus, the formulated yoghurt powder could be considered as a potential functional powder with antioxidant properties.
... bulgaricus. This fermentation leads to acidification and milk coagulation (Corrieu and Béal 2016). Yoghurt has become one of the prevalent choices and considered as a healthy food since it provides excellent sources of essential nutrients (Fazilah et al., 2018). ...
... On the other hand, Water-Holding Capacity is one of the desirable features for yoghurt quality which is related to the water keeping ability of proteins within the yoghurt curd Demirci et al. (2017). According to Corrieu and Béal (2016) syneresis is, generally, affected by the protein content and physical treatments of the mix. As shown in Table 2 Table 2. Results show that firmness value increase significantly (p<0.05) after addition of 0.5 % of PPP and 5 % of honey. ...
Article
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Pomegranate (Punica granatum L.) peels and honey are rich in bioactive compounds and are promising as natural ingredients for functional product development. This study aimed to develop a novel yoghurt fortified with pomegranate peel and honey, and to investigate their effect on the sensory, physicochemical, textural, microbiological, and antioxidant properties throughout storage period (28 days). Fortification of yoghurt with 5 % of honey and 0.5 % of pomegranate peel powder showed a positive effect on several determinative properties such assyneresis, water-holding capacity, color, instrumental texture and sensory attributes. After the whole storage period, fortified yoghurt presented the same count of total lactic acid bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus) as the control yoghurt that remained over 10 7 CFU/g. In addition, fortified yoghurt contained more polyphenols (nearly 7 fold higher) and displayed significantly (p<0.05) higher antiradical activity (DPPH and ABTS radical scavenging activity) than control yoghurt. In conclusion, fortification of yoghurt with 5 % of honey and 0.5 % pomegranate peel powder offered a novel yoghurt with acceptable sensory characteristics, good physicochemical and textural properties, and interesting antioxidant activity without inhibiting the development of lactic acid bacteria.
... bulgaricus). After fermentation, the milk acidifies and coagulates and increases the shelf life due to the low pH [2]. ...
... The critical thinking learning model developed and applied is described in Figure 1. Through the learning process three stages were identified: (1) Evaluation of information; (2) description/identification of problems as main concept; and (3) analysis (interpretation and inferences). The evaluation of information is based on gathering and reporting data, facts, observations, and experiences that should be clear, relevant, accurate, adequate, and consistent. ...
Article
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The present study describes the implementation of a food safety system in the dairy pilot plant “Gourmeticus Academicum,” a spin-off within the University of Agricultural Sciences and Veterinary Medicine of Cluj Napoca, Romania. In order to improve Hazard Analysis of Critical Control Points (HACCP) the preliminary programs were integrated into the quality management system (QMS) by monitoring the biological hazards. The process provides future specialists with good practice hands-on and educational tools. This study focused on hazard analysis, the determination and establishment of prerequisite programs, and the role of critical control points (CCPs) based on HACCP and the challenges found during the process as a critical thinking model on education programs. The determination of the CCPs in the processing of yogurt was made by applying the decision tree method. Besides, biological hazards are included as a by-control of the system’s implementation performance. For the successful implementation of HACCP principles, prerequisite programs (PRPs) and operational prerequisite programs (OPRPs) were initially implemented. This process could be challenging but feasible to be reached in small-scale food industries with remarkable results as educational tools.
... Yoghurt is a dairy product produced through the action of lactic acid bacteria (LAB) on milk. The action of these bacteria leads to the acidification and coagulation of milk [1]. Yoghurt is one of the most commonly consumed products among different populations owing to its intrinsic benefits [2]. ...
... 5 g of each sample was placed in an oven dryer at 105°C for 3h, the initial mass before drying and the final mass after drying was measured and used in the determination of the total solids. (1) Where; M 3 -the mass/weight of the sample and Petridish after drying, M 2 -the mass/weight of sample and Petri dish before drying and M 1 -the mass/weight of the empty Petridish. ...
Conference Paper
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Yoghurt is a probiotic food readily consumed among different populations owing to its nutritional and intrinsic benefits. This product serves as an excellent source for fortification with other bioactive compounds making it a suitable vehicle for fortification with Moringa oleifera which contains a substantial quantity of bioactive compounds. This study evaluates the physicochemical parameters of low-fat yoghurt enriched with Moringa oleifera leaf powder during 14 days of storage at 4±1⁰C. Five samples of low-fat yoghurt were produced and coded samples 1, 2, 3, 4, and 5. Sample 1 served as the control sample, while samples 2, 3, 4, 5 were low-fat yoghurt enriched with moringa leaf powder at 0.3%, 0.5%, 0.7%, 1.0%, respectively. The pH of the samples at different concentrations was significantly different (p<0.05) ranging from 4.517 to 4.260 and decreased in all samples during storage while there was a significant increase in titratable acidity of the samples (0.780% to 1.410%) during storage. Water holding capacity (WHC) was found to be higher in samples fortified with moringa as compared to the control and syneresis significantly reduced in samples fortified with moringa. There was a significant difference (p<0.05) between the viscosity of samples with different moringa concentrations besides, samples fortified with moringa leaf powder were higher in viscosity than the control sample. Sample 5 which had the highest concentration of moringa was low in viscosity, WHC and higher in total solids in comparison to the control. Based on the data obtained from this present study, samples with a lesser concentration of moringa are recommended for further studies as they enhance the physicochemical properties of yoghurt.
... bulgaricus. This fermentation leads to acidification and milk coagulation [13]. ...
... The discovery and emergence of the milk fat globule membrane in the last two decades, has increasingly drawn the attention of many researchers around the world, due to its wide range of applications, not only that, including extraction, isolation, and purification techniques. The need for functional foods is increasing daily, of which set yoghurt is regarded as one, considering its wide range of therapeutic properties and functions towards human health (Lee and Lucey, 2004;Aziznia et al., 2008;Hassan et al., 2015;Corrieu and Béal, 2016). In addition, a combination of milk fat globule membrane (MFGM), an important novel food ingredient, with milk to produce yoghurt, not only supply nutritional and health benefits, but also provide technological functionality in order to eliminate some obvious problems in yoghurt production, which include syneresis, low gel strength, poor appearances, and taste changes, etc. ...
Article
Lacprodan®PL20, a material rich in protein and polar lipids, was incorporated into set yoghurts produced from non-homogenized raw milk. The set yoghurts were prepared using 2, 4 and 6% Lacprodan®PL20 concentrations, but the control sample was only supplemented with skim milk powder. The effect of Lacprodan®PL20 on the physical, chemical properties, rheology and microstructure of set yoghurts was thoroughly investigated to examine some likely improvement and changes. It was observed that Lacprodan®PL20 gradually improved the set in nutritive values, water holding capacity, and apparent viscosity. Also, it altered the firmness and steadily improved the gel strength, especially at 4 and 6% levels with a noticeable comparison with the control sample. The pH values showed a slight delay in the fermentation process at 4 and 6% concentrations and slightly increased the pH, as the concentration increased. The microstructure of the set yoghurts produced with Lacprodan®PL20, as examined by scanning electron microscopy showed a much thicker structure with less and smaller holes in the gel matrix. Also, the appearance had a slight similarity between the samples especially the color b*(-blue to +yellow) but decreased as the concentration increased. Moreover, no significant differences were observed in the L* (lightness) and a* (-green to red) colors of the samples. These results vividly showed that Lacprodan®PL20, an enriched milk fat globule membrane fragment, has the potential to improve significantly the quality of set yoghurt, therefore, reducing some defects associated with set-yohurt such as syneresis, low gel strength, low dry solids, and the likes, by providing the required functions.
... According to the increase in yogurt consumption [15], it is important to seek new opportunities to expand their offers to consumers and to develop products enriched with health substances at various stages of production, as well as in gastronomy or home conditions. The use of fiber as a food additive modifies its physical properties [11] and therefore it is valid to investigation the rheological properties and stability of the obtained systems using modern techniques. ...
Article
Full-text available
The influence of the amount of inulin addition (3%, 6%, 9%, 12% or 15% w/w) on the physicochemical properties of natural yogurt was analyzed. The acidity (titration; pH), texture parameters (penetration test), viscosity curves (rotational rheometer), microrheology (macroscopic viscosity index, MVI; elasticity index, EI; solid-liquid balance—SLB; multi-speckle diffusing-wave spectroscopy, MS-DWS) and physical stability (syneresis; LUMiSizer test) of yogurts were investigated. All samples were non-Newtonian pseudoplastic liquids. The sample with 15% inulin content presented an approx. 4% higher pH value (4.34), 3-fold greater MVI and almost 5-fold higher penetration force, compared to the control sample (0% of inulin). In turn, the use of inulin addition in the range of 3–15% w/w resulted in a reduction of syneresis (p < 0.05). A linear decrease in the values of instability indexes and sedimentation velocities was noted in the function of inulin content increase (LUMiSizer test). The application of inulin (in the range of 3–15% w/w) as a functional additive to yogurts significantly contributed to enhancement of their physical stability. Summing up, the possibility of obtaining natural yogurts with a high content of this prebiotic has been demonstrated, thus such products can be classified as functional foods and a health claim can be put on the label.
... Total lactic acid bacteria ranged from 3.7 x 107 to 2.6 x 108 CFU mL-1 in accordance with SNI standards (2009). Corrieu and Beal (2016) stated that two thermophilic lactic acid bacteria, namely S. thermophilus and L. delbrueckii subsp. bulgaricus, which triggers yoghurt in fermentation, is considered safe. ...
Article
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Ciomas Rahayu Village, Bogor Regency is an area with populated densely. Knowledge of the benefits and making of Yoghurt for moms of family welfare coaching is very important. Because Yoghurt has been shown to improve the body's immune system and overcome lactose intolerance. The purpose of this program was provide counseling and accompanying about the making of yoghurt for the family as well as explanation of the benefits of yoghurt if consumed. Activity method was practice in making yoghurt from basic ingredients of milk and were given starter to be fermented by moms of family welfare coaching Ciomas Rahayu Village Bogor Regency on 30 people cadres. Milk was fermented in a bottle is done for 2 x 24 hours at a temperature of 37oC-42oC. Fermentation results were added sugar expected can make the family business knowledge. Evaluation of Yoghurt production results done that moms can make yoghurt well so that result satisfactory. To do business need existence of cooperation with other party funding. Outcome of this activity was the increasing understanding and skill of partner of Ciomas Rahayu Village, Bogor Regency in making Yoghurt and increasing family business skill.
... After 60 days of storage, there was no significant difference (P > 0.05) in the amount of lactic acid between yogurt. The results presented in this work agree with the aforementioned data (Corrieu and Béal, 2016). ...
Article
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Lactobacillus casei enriched apple pieces, dried raisins and wheat grains were incorporated in yogurt in fresh and freeze dried form to produce a novel probiotic dairy product. The viability of L. casei cells was assessed in the yogurts during storage at 4 °C for 60 days and the effect of the added enriched materials on physicochemical parameters, microbiological characteristics and sensory acceptance of yogurts were evaluated. The apples, raisins and wheat grains improved the viability of embedded L. casei cells resulting at counts around 7 logcfug⁻¹ of yogurt after 60 days of storage at 4 °C. Yogurts produced with incorporation of L. casei enriched raisin and wheat grains in particular, presented less syneresis due to their water holding capacity. The above results are encouraging for the production of novel yogurts with improved sensorial and nutritional characteristics in industrial and/or small industrial scale.
... The high final pH value of the F-fermented YAs can also represent a safety risk, as the low pH derived from the production of organic acids is crucial in pathogen inhibition, especially in a YA containing lupin protein isolate, in which Bacillus cereus can be present (Fritsch et al., 2015). In the case of yogurts, pH values range from 4.5 to 4.8, which is the usual target considered for having safe products (Corrieu and Béal, 2016). We also hypothesize that the high proteolysis observed in the F-fermented YAs (Fig. 3A and B) leads to more peptides and free amino acids, as shown by a higher level of free NH 2 released (Fig. 3C) and therefore could have modified the textural properties. ...
Article
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Food transition requires incorporating more plant-based ingredients in our diet, thus leading to the development of new blant-based products, such as yogurt alternatives (YAs). This study aimed at evaluating the impact of lactic acid bacteria (LAB) cocultures and formulation on the physico-chemical and sensory properties of YAs. YAs were made by emulsifying anhydrous milk fat (AMF) or coconut oil in milk and lupin protein suspensions. The starters used, in mono- and cocultures, were the strains Lactococcus lactis NCDO2125, Enteroccocus faecalis CIRM-BIA2412 and Lactiplantibacillus plantarum CIRM-BIA1524. Textural properties and metabolites of YAs were evaluated and their sensory properties compared using a sorting task. Some cocultures led to higher firmness, viscosity, and water holding capacity of YAs, compared to monocultures. AMF and a milk:lupin protein ratio of 67:33 gave firmer and more viscous YAs. YAs were sensorially discriminated on the basis of protein ratio and fat type, but not of starters. The cocultures exhibited more diverse functional outputs, such as texturing, production of flavour compounds, proteolysis, when the strains associated in coculture had distinct capacities. Appropriate associations of LAB and formulation offer interesting solutions to improve the perception of YAs, and ultimately, encourage their consumption.
... Nowadays, healthy habits and nutrition consciousness of consumers have resulted in rising demand for fruits containing high flavonoid content utilizing fortification. Yogurt is a coagulated milk product resulting from the fermentation of lactose in milk by Lactobacillus bulgaricus and Streptococcus thermphilus (Corrieu et al., 2016) (Eslampour et al., 2020;Yada et al., 2013). In another study, dark chocolates are confirmed as an excellent source of magnesium and iron and chocolate containing 90% cocoa is believed to be a good source of zinc and selenium that is important for our immune system (Cinquanta et al., 2016). ...
Article
Converting wastes to valuable products is the main target for many kinds of research nowadays. Wastes represent an environmental problem and getting rid of it is not easy and causes pollution. Accordingly, this study offers production of the valuable enzyme β-galactosidase using rice straw and orange peel as the main medium constituents. β-galactosidase converts lactose to glucose and galactose which are simple sugars and can be fermented easily by lactose-intolerant people who represent more than 50% of the world’s population. It was produced by Lactobacillus paracasei, a series isolated from fermented milk, identified using 16S ribosomal RNA gene partial sequence and had the accession number MK852178. Plackett–Burman (PB) and Central Composite (CCD) Designs optimized the production scoring 1.683(10)⁶ U/ml with a difference five times higher than the non-optimized medium. The addition of 0.3 or 0.6% of β-galactosidase serves as a good fortification for manufacturing nutritional and therapeutic low-lactose yogurt with no significant differences in total protein, total solids, fat, and ash between control and all treatments. The chemical, rheological and sensory properties of the final produced yogurt were evaluated during storage periods up to 9 days at 5 °C. In conclusion, L. paracasei MK852178 β-galactosidase is a promising additive in manufacturing low lactose yogurt for lactose-intolerant people since it reduces the lactose content and doesn’t influence the chemical and sensory properties.
Article
Aims: The present work investigates the effect of tartary buckwheat flavonoid (TBF) capsules on the physical and chemical properties of yoghurt using polymeric whey protein (PWP) as a wall material. Methods: PWP was prepared by thermal polymerisation. TBF was encapsulated using PWP as the wall material via the pore-coagulation bath method. The physicochemical properties of the TBF capsules, such as the entrapment yield, moisture, average particle size, particle size distribution, surface morphology, molecular interactions, and thermal stability were investigated, in addition to the release of TBF in simulated gastric and intestinal juices. Yoghurt formulation was carried out using encapsulated TBF (3%, w/w), blank PWP beads (2.7%, w/w), and unencapsulated TBF (0.3%, w/w). A control yoghurt sample was prepared without these ingredients. The effects of encapsulated TBF on the chemical composition, acidity, texture, synaeresis, sensory properties, number of Streptococcus thermophilus and Lactobacillus, and other physical and chemical properties of the yoghurt were investigated. Results: TBF capsules were found to be sphere-shaped with porous surfaces, an average particle size of 1728.67 μm, an encapsulation yield of 92.85 ± 1.98% (w/w), and a glass transition temperature of 152.06 °C. When the TBF capsules were exposed to simulated gastric fluid for 4 h, the TBF release rate was 15.75% (w/w), while in simulated intestinal fluid, the TBF release rate reached 65.99% (w/w) after 1 h. After 5–6 h in simulated intestinal fluid, the TBF release rate reached 100% (w/w). The protein content of the yoghurt with encapsulated TBF was 3.57 ± 0.26% (w/w, p < 0.01), and the numbers of Lactobacillus and Streptococcus thermophilus were 2.45 ± 0.98 × 10⁸ (p < 0.01) and 5.43 ± 2.24 × 10⁷ CFU/mL (p < 0.05), respectively, with strong water retention being detected (p < 0.01). Samples containing the encapsulated TBF exhibited a significantly higher acceptability than the unencapsulated TBF (p < 0.01). Conclusions: Encapsulation using PWP effectively delivers TBF to the small intestine through the stomach. It also masks the bitter taste, enhances the colour of TBF-containing yoghurt, and improves the physical and chemical properties of the yoghurt.
Chapter
Fermented foods have a profound probiotic value and share an integral part of age-old wisdom from ancient civilizations across the globe. Over decades of human history the pioneering practice of food fermentation has added taste to cultural ethos and has expanded significantly from household level to gradually improve the available food resources combat the hidden hunger. Consumer demand for these healthier foods with balanced nutrient profile along with metabolic, health, functional, nutritional, and nutraceutical benefits has gained pace that been derived from anecdotal evidence of their effect against chronic diseases. Fermented foods act as a sink of beneficial microorganisms with various health-promoting functions like preventing intestinal tract infections, decreasing cholesterol level, enhancing lactose metabolism, immunity, calcium absorption, protein digestibility, synthesis of vitamins (vitamin B, nicotinic acid, and folic acid), and counteracting effect of foodborne pathogens. Most of the fermented foods are derived from fruits, vegetables, dairy and some are cereal based as well. In this chapter, some explorative information on traditional fermented fruit, vegetable, dairy, and rice-based foods and beverages has been assembled to illustrate their functional aspects. The chapter deals with production, traditional processing, probiotic and therapeutic values of various probiotic dairy-based foods like cheese, yoghurt, and kefir; some plant-based foods that are widely consumed (kimchi, sauerkraut, pickles, kombucha, kefir, tempeh, yoghurt, miso, etc.); and various South Indian traditional cuisines like idli and dosa to encourage entrepreneurs to develop large-scale production and meet the growing market demand of functional foods.
Article
Lactic acid bacteria such as Lactobacillus bulgaricus and Streptococcus thermophilus in yogurt maintains the balance of the intestinal microflora by suppressing the growth of harmful bacteria. Dietary fibre and functional compounds in probiotic drinks also have a good effect on health. The modification of low-fat probiotic drinks is a value-added product and can be classified as a healthy drink. Caulerpa racemosa is a Chlorophyceae seaweed with high food fibre and functional compounds, including phenolic and chlorophyll as antioxidants. This study aimed to determine the effect of different lactic acid bacteria on the characteristics of the probiotic drink products by combining C. racemosa with low-fat cow’s milk. C. racemosa and low-fat cow’s milk with a ratio of 3:4 was fermented with Lactobacillus bulgaricus (A), Streptococcus thermophilus (B), and a combination of both (C). The products were analysed for protein and fat content, dietary fibre, total phenolic content, antioxidants activity, total lactic acid bacteria, total acid, pH, and with a sensory test for consumer preference. The addition of the different lactic acid bacteria had effects on the fat, antioxidants, dietary fibre, and total acid contents, while protein and total phenolic contents were not significantly different. The combination of L. bulgaricus and S. thermophilus produced a probiotic drink with the lowest amount of dietary fibre (1.27%) and total acid (0.64%), with antioxidant activity IC50 of 183.57 ppm and total phenolic content of 0.11 mg GAE/g. The preference test showed that the panellists preferred yogurt fermented with L. bulgaricus and S. thermophilus for its aroma, texture, and colour.
Chapter
From harvest to distribution, the food industry’s application is as old as the industry itself. Conventional technologies such as pasteurization, homogenization, and direct microscopic count are well established and practiced mainly in the dairy industries. However, there is a need to evolve these technologies due to food security, changing consumer needs, environmental concerns, economic viability, and policy reforms. Apart from this, today’s food industry is also facing several challenges related to food safety, preservation, nutrition, and allergies. Therefore, the presently used technologies in the production, processing, packaging, and safety of various dairy products need to evolve further to overcome these challenges. Here we review the potential applications of food safety tools like hazard analysis and critical control point, sustainable packaging materials like polylactic acid, and non-conventional technologies such as ultrasound to solve current problems. This chapter discusses the role of various biotechnologies in food packaging, processing, and safety, focusing on different dairy products, from indigenous to by-products. The food industry also needs to identify and overcome socioeconomic challenges to proceed with these non-conventional, relatively new technologies from laboratory to industry.
Article
Rice is a staple food for a great part of the world's population, and its processing generates a great volume of low value by‐products, such as bran and broken grains. This work aimed to elaborate fermented rice by‐products extracts with probiotic strains and with different waxy maize starch (WMS) contents (0, 4, 8, 12 and 16% w/w), in order to select one with texture profile similar to Greek‐style yogurt; and to characterize the chemical composition and sensory acceptance of the selected extract added with artificial strawberry aroma and fresh strawberry syrup. The texture profile of the extract changed with WMS content and the 4% WMS fermented rice by‐products extract was the most similar to Greek‐style yogurt. The flavored fermented rice by‐products with WMS product presented 72.67% moisture, 2.55% protein, 0.2% lipid, and 0.8% ash (340 mg 100 g−1 of potassium), 27.4 μmol Trolox g−1, and 134.74 mg GAE 100 g−1 of phenolic compounds. The flavored fermented rice by‐products extract did not show microbiological risk and presented probiotic characteristic. Regarding the sensory analysis, it was observed that the aroma stood out among the other attributes, obtaining the highest score and acceptance index, while color, flavor, and texture scored ‘liked regularly to moderately'. The flavored fermented rice by‐products extract is an innovative product and feasible regarding the technological, physical, chemical, microbiological and sensory characteristics, having great potential to be inserted into the market. This article is protected by copyright. All rights reserved.
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Yoghurt is most popular and more acceptable throughout the world because of its general positive image among consumers because of its diverse nutritional and therapeutic properties and can be the most suitable probiotic carrier. Key factors for consumer’s inclination towards functional foods are increased awareness for healthy foods because of health deterioration resulting from busy lifestyles, growing healthcare cost and the aspiration for an improved quality life in later years. Yoghurt is still not consumed in certain parts of the world because of a lack of a cultural tradition of consuming yogurt and further people are not aware of the health benefits associated with yogurt consumption. In this study an attempt has been to project probiotic yoghurt as a functional food in the current era of self-care and complementary medicine. Attempt has been made to review the literature on the biochemical activities of yoghurt cultures and theirbehavior in association with diverse probiotic cultures. Both review and research papers related to biochemical activities and functional properties of yoghurt cultures in association with probiotics and their health benefits published in diverse journals under Pub Med and Science Direct have been considered. Keywords used for data search included functional foods, yoghurt, probiotic, health benefits, etc.Functional properties of yoghurt can be further enhanced with fortification of minerals and vitamins or inclusion of probiotic cultures. Diversity in biochemical behavior yoghurt cultures in association with different probiotic cultures has been reported. Conjugated application of probiotics with yoghurt cultures would result in a product with enhanced functional properties to extend health benefits.
Chapter
Yogurt is a fermented dairy food traded worldwide and eaten by all groups in different societies. Yogurt is also a good delivery system for many nutrients and bioactive ingredients and is a suitable medium for fortifying many vital compounds that have a role in improving and preventing human health. There are many developments in the technology of yogurt production; the most important of which is to increase its acceptance by improving its technological properties. Development includes supporting it with many dairy and other nondairy components to increase its health and nutritional value, as well as adding some fruits and others to improve taste and increase acceptance, as it is primarily used to deliver beneficial bacteria (probiotic) for their role in improving health. Incorporation of probiotic organisms into dairy food items to increase the nutritional status with the added therapeutic characteristics is practiced worldwide, especially in countries like Japan, United States, Australia, and Europe. Probiotics are generally mono or mixed cultures of live microorganisms which form the major component of the gut flora (e.g., Lactobacilli, Bifidobacteria). Probiotics, when ingested beneficially, affect the host by replenishing the depleted gut microflora, which may have occurred due to the use of antibiotics, illness or stress, travel or lifestyle changes; it also improves the properties of the indigenous microflora of the host. Microbial strains for probiotic use must be representative of microorganisms that are generally recognized as safe microbes. The health of women and their interest in them is important and reflects positively on society. Recent studies focus on the existence of effective methods to treat the symptoms and complications associated with women after menstruation. Because of these symptoms of health problems—followed by psychological problems that lead to economic difficulties on the family scale, which in turn reflects on society as a whole—adding types of probiotic bacteria to some additives help to solve and overcome those effects. In this chapter, we will review the most important technological developments as well as objectives of yogurt that have been addressed in the studies, and we will focus on the role of these developments and their relationship to women’s health.
Article
Osmoporation is a novel encapsulation approach for bioactive compounds based on the osmoresistance mechanisms of microbial cells. To the best of our knowledge, this is the first study investigating the production of fisetin-enriched yoghurt using Lactobacillus acidophilus-based bio-capsules via osmoporation as the starter culture. Results showed that the milk acidification with fisetin-loaded L. acidophilus progressed at a slower pace due to complex mechanisms induced by osmoporation and internalized fisetin. Milk fermentation using fisetin bio-capsules reached a maximum acidification rate of 0.18 pH units/h after 23 h and pH 4.6 was achieved after 32 h. Besides, the antioxidant activity of yoghurts produced with fisetin bio-capsules did not change during cold storage, while the antioxidant activity of yoghurt produced with non-encapsulated fisetin was reduced by 2.5-fold after 28 days. Overall, this study shows that fisetin osmoporation using L. acidophilus is a versatile encapsulation bioprocess that enables the delivery of preserved phytoactives into fermented foods like yoghurt. This strategy has the potential to be extended to other applications in the dairy industry using lactic acid bacteria as both the encapsulation matrix and fermentation agent.
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Yogurt gels are a type of soft solid, and these networks are relatively dynamic systems that are prone to structural rearrangements. The physical properties of yogurt gels can be qualitatively explained using a model for casein interactions that emphasizes a balance between attractive (e.g., hydrophobic attractions, casein cross-links contributed by calcium phosphate nanoclusters and covalent disulfide cross-links between caseins and denatured whey proteins) and repulsive (e.g., electrostatic or charge repulsions, mostly negative at the start of fermentation) forces. Various methods are discussed to investigate the physical and structural attributes of yogurts. Various processing variables are discussed which influence the textural properties of yogurts, such as total solids content, heat treatment, and incubation temperatures. A better understanding of factors contributing to the physical and structural attributes may allow manufacturers to improve the quality of yogurt.
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Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.
Article
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Interactions among lactic acid starter and probiotic bacteria were investigated to establish adequate combinations of strains to manufacture probiotic dairy products. For this aim, a total of 48 strains of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium spp. (eight of each) were used. The detection of bacterial interactions was carried out using the well-diffusion agar assay, and the interactions found were further characterized by growth kinetics. A variety of interactions was demonstrated. Lb. delbrueckii subsp. bulgaricus was found to be able to inhibit S. thermophilus strains. Among probiotic cultures, Lb. acidophilus was the sole species that was inhibited by the others (Lb. casei and Bifidobacterium). In general, probiotic bacteria proved to be more inhibitory towards lactic acid bacteria than vice versa since the latter did not exert any effect on the growth of the former, with some exceptions. The study of interactions by growth kinetics allowed the setting of four different kinds of behaviors between species of lactic acid starter and probiotic bacteria (stimulation, delay, complete inhibition of growth, and no effects among them). The possible interactions among the strains selected to manufacture a probiotic fermented dairy product should be taken into account when choosing the best combination/s to optimize their performance in the process and their survival in the products during cold storage.
Article
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The manufacture of yoghurt relies on the simultaneous utilization of two starters: Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (Lb. bulgaricus). A protocooperation usually takes place between the two species, which often results in enhanced milk acidification and aroma formation compared to pure cultures. Cell-wall proteinases of Lactococcus lactis and lactobacilli have been shown to be essential to growth in milk in pure cultures. In this study, the role of proteinases PrtS from S. thermophilus and PrtB from Lb. bulgaricus in bacterial growth in milk was evaluated; a negative mutant for the prtS gene of S. thermophilus CNRZ 385 was constructed for this purpose. Pure cultures of S. thermophilus CNRZ 385 and its PrtS-negative mutant were made in milk as well as mixed cultures of S. thermophilus and Lb. bulgaricus: S. thermophilus CNRZ 385 or its PrtS-negative mutant was associated with several strains of Lb. bulgaricus, including a PrtB-negative strain. The pH and growth of bacterial populations of the resulting mixed cultures were followed, and the Lactobacillus strain was found to influence both the extent of the benefit of Lb. bulgaricus/S. thermophilus association on milk acidification and the magnitude of S. thermophilus population dominance at the end of fermentation. In all mixed cultures, the sequential growth of S. thermophilus then of Lb. bulgarius and finally of both bacteria was observed. Although proteinase PrtS was essential to S. thermophilus growth in milk in pure culture, it had no effect on bacterial growth and thus on the final pH of mixed cultures in the presence of PrtB. In contrast, proteinase PrtB was necessary for the growth of S. thermophilus, and its absence resulted in a higher final pH. From these results, a model of growth of both bacteria in mixed cultures in milk is proposed.
Article
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Yogurt is a milk curd produced all over the world, obtained by a lactic fermentation of a milk base enriched with milk proteins, and sometimes sugars and thickeners. One of the most important sensorial attributes for yogurt is texture, which could be assessed by sensory or instrumental analysis. A lot of work has been published in studying the contribution of milk base, starter, and process on yogurt texture in order to develop new textures, or simply to reduce fat content, or the level of addition of protein and thickener in milk. However, these studies are limited to only a few factors. The topic of this review was to synthesize the data of literature, with the aim of extracting and classifying factors on the basis of their influence on yogurt texture. Three factors, milk base heating, starter, and yogurt shearing after fermentation, respectively, play a key role in the elaboration of texture. The control of these three parameters allows the improvement of the textural attributes of yogurts by 2 to 15 times.
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The ability to produce exopolysaccharides (EPS) is widespread among lactic acid bacteria (LAB), although the physiological role of these molecules has not been clearly established yet. Some EPS confer on LAB a "ropy" character that can be detected in cultures that form long strands when extended with an inoculation loop. When EPS are produced in situ during milk fermentation they can act as natural biothickeners, giving the product a suitable consistency, improving viscosity, and reducing syneresis. In addition, some of these EPS may have beneficial effects on human health. The increasing demand by consumers of novel dairy products requires a better understanding of the effect of EPS on existing products and, at the same time, the search for new EPS-producing strains with desirable properties. The use of genetically modified organisms capable of producing high levels of EPS or newly designed biopolymers is still very limited. Therefore, exploration of the biodiversity of wild LAB strains from natural ecological environments is currently the most suitable approach to search for the desired EPS-phenotype. The screening of ropy strains and the isolation and characterization of EPS responsible for this characteristic have led to the application over the past years of a wide variety of techniques. This review summarizes the available information on methods and procedures used for research on this topic. The information provided deals with methods for screening of EPS-producing LAB, detection of the ropy phenotype, and the physicochemical and structural characterization of these molecules, including parameters related to their viscosifying properties. To our knowledge, this is the first compilation of methods available for the study of EPS produced by LAB.
Data
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Article
Fermented foods and beverages possess various nutritional and therapeutic properties. Lactic acid bacteria (LAB) play a major role in determining the positive health effects of fermented milks and related products. The L. acidophilus and Bifidobacteria spp are known for their use in probiotic dairy foods. Cultured products sold with any claim of health benefits should meet the criteria of suggested minimum number of more than 10(6) cfu/g at the time of consumption. Yoghurt is redefined as a probiotic carrier food. Several food powders like yoghurt powder and curd (dahi) powder are manufactured taking into consideration the number of organisms surviving in the product after drying. Such foods, beverages and powders are highly acceptable to consumers because of their flavor and aroma and high nutritive value. Antitumor activity is associated with the cell wall of starter bacteria and so the activity remains even after drying. Other health benefits of fermented milks include prevention of gastrointestinal infections, reduction of serum cholesterol levels and antimutagenic activity. The fermented products are recommended for consumption by lactose intolerant individuals and patients suffering from atherosclerosis. The formulation of fermented dietetic preparations and special products is an expanding research area. The health benefits, the technology of production of fermented milks and the kinetics of lactic acid fermentation in dairy products are reviewed here.
Article
The time dependent rheological behaviour of 4 commercial stirred yoghurts was evaluated at constant shear rate within the range 18 to 280 s-1.The viscosity decreased greatly to an equilibrium value after 600 s of shearing. A simple model based on a structural approach was used. A rheological test was designed and carried out at a constant shear rate of 111 s-1 and a temperature of 10C. Three types of stirred yoghurt processed in the laboratory under standard conditions were compared with the 4 commercial brands. Two parameters of the model were highly significant for comparing the different stirred yoghurts. These were the rate constant of the structural decay and the consistency index at equilibrium.
Article
The influence of packaging polymers (polypropylene or polystyrene) on the sensory and physicochemical characteristics of flavoured stirred yogurts with either 0% or 4%-fat content was investigated during the 28 days of storage at 4°C. Regardless of the packaging type, complex viscosity and thickness perception increased during storage due to exopolysaccharide production, whereas the pH of yogurts decreased. Packaging type had a greater impact on 0%-fat yogurts than on 4%-fat yogurts for both sensory and physicochemical characteristics. During storage, 0%-fat yogurt conditioned in glass displayed the lowest aroma quantity decrease of the three types of packaging, in accordance with the olfactory properties. However, between the two polymer types, polystyrene packaging seemed to be preferable for limiting aroma compound losses and subsequent fruity note intensities, and for avoiding the development of odour and aroma defects. Less significant packaging effect was observed for 4%-fat yogurts. Copyright © 2008 Elsevier Ltd. All rights reserved.
Article
Yoghurt: Science and Technology is a standard work in its field for both industry professionals and those involved in applied research. Because manufacture is still, essentially, a natural biological process, it remains difficult to control the quality of the final product. Such control depends on a thorough understanding of the nature of yoghurt and both the biochemical changes and process technologies involved in production. Yoghurt: Science and Technology provides just such an understanding. Since the last edition, the industry has been transformed by the introduction of mild-tasting "bio-yoghurts", changing both consumer markets and manufacturing practices. This new edition has been comprehensively revised to take on board this and another major developments in the industry. Thus, today, millions of gallons of yoghurt are produced each year, yet manufacture is still, in essence, a natural biological process in which success can never be taken for granted. It is this capricious nature of the fermentation that leaves the system prone to variation. So, though some aspects of production of yoghurt have become fairly standard, there are so many areas of potential difficulty. This book offers preliminary guidance on the intricacies of production and distribution of yoghurt so as to minimize product failure.
Health and nutritional properties of probiotics in food including powder milk with live lactic acid bacteria: report of a joint FAO/WHO expert consultation
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FAO/WHO (2001) Health and nutritional properties of probiotics in food including powder milk with live lactic acid bacteria: report of a joint FAO/WHO expert consultation. Cordoba, Argentina: FAO/WHO.
Codex Alimentarius: codex standards for fermented milks 243-2003 Milk and milk products
  • Fao Who
FAO/WHO (2011) Codex Alimentarius: codex standards for fermented milks 243-2003. In: FAO/WHO (ed.) Milk and milk products, 2nd ed., pp. 6–16. Rome: FAO/WHO.
Methods for the screening, isolation, and characterization of exopolysaccharides produced by lactic acid bacteria
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Ruas-Madiedo P and de los Reyes-Gavilán CG (2005) Methods for the screening, isolation, and characterization of exopolysaccharides produced by lactic acid bacteria. Journal of Dairy Science 88: 843–856.
Automated system to follow up and control the acidification activity of lactic acid starters
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Corrieu, G., Spinnler, H. E., Jomier, Y. and Picque, D. (1988). Automated system to follow up and control the acidification activity of lactic acid starters. Fr. Pat. 2 629 612.
Rheological Properties of Food Materials; Yogurt: Dietary Importance; Yogurt: Yogurt Based Products
  • Probiotics
Probiotics; Rheological Properties of Food Materials; Yogurt: Dietary Importance; Yogurt: Yogurt Based Products. Further Reading