H. Mu's research while affiliated with Zhejiang Academy of Agricultural Sciences and other places

Publications (27)

Walnut (Carya cathayensis Sarg.) oil contains over 85% of unsaturated fatty acids, which are easily oxidized during storage. As a result, a large number of volatile oxidation compounds (VOCs) are formed during oxidation. The qualitative composition of VOCs in walnut oil and quantitative prediction of the oxidation parameters (peroxide value, acid value and p‐anisidine value) by VOCs were investigated through SPME/GC‐MS combined with partial least‐squares (PLS) regression analysis. Eighteen volatile oxidation compounds including aldehydes, alcohols, and acids were detected by SPME/GC‐MS. According to the comprehensive scores of principal component analysis (PCA), 2‐octenal, hexanal, 2‐heptenal, 1‐octen‐3‐ol, hexanoic acid and nonanal were the main products formed during oxidation. Then PLS regression was applied to developing quantitative prediction models of oxidation parameters (peroxide value, acid value and p‐anisidine value) by VOCs. The PLS prediction models had a good performance, with determination coefficients (R²p) of 0.993‐0.997 for the prediction sets of the three oxidation parameters. Practical applications: The quantitative relationship between VOCs and oxidation parameters was developed in this study, which provided a new method for monitoring the quality of walnut oil. The SPME/GC‐MS combined with PLSR was a feasible and potential method for simultaneous qualitative and quantitative analysis of oxidation process. This method was proven to have a precise predictive ability and provided a potential application in the quality assessment of other nut products.
We investigated the relationship between the pre-drying temperature and overall quality of dried shiitake mushrooms (Lentinula edodes). Results showed that high-temperature pre-drying significantly increased the rehydration ratio and hardness of dried shiitake mushrooms, but decreased the degree of shrinkage, degree of browning, and formaldehyde content. The levels of enzyme activity were high throughout the pre-drying process and benefitted the formation of flavoured substances. Furthermore, high-temperatures pre-drying also resulted in a higher content of sulfur compounds. These results indicated that the pre-drying processing had significant impacts on the overall quality of dried shiitake mushrooms. This may pave the way for increasing the economic value of dried shiitake mushrooms.
The composite bilayer film based on polyvinyl alcohol, sodium alginate, and chitosan were developed in this study, and the effects of the related coating on internal-quality changes of salted duck eggs (SDEs) during storage were determined. The results showed that the overall properties of the bilayer film were better than those of monolayer films, including storage stability. Coatings could significantly (p < 0.05) reduce quality deterioration of SDEs such as water loss, oil exudation, and gritty. The bilayer coating was more effective in inhibiting the increase of egg yolk pH and total bacterial counts than monolayer coatings. After storage for 60 days, water content of bilayer coated SEDs was 19.7% higher than that of the control SDEs, oil exudation was 38% higher, and gritty texture was 27.9% higher. Moreover, bilayer coating could prolong the shelf life of SDEs to more than 60 days at 25°C and 50% relative humidity according to the results of total bacterial count experiment, while the shelf life of control SDEs was less than 45 days. This study indicated the potential application of bilayer composite coating for preservation of SDEs.
Nuts are full of unsaturated fatty acids, and have antioxidant and anti-aging activities. The consumption of nut products may reduce risks of heart disease. However, unsaturated fatty acids are unstable, which lead to oxidative rancidity of nuts duringpostharvest preservation, processing and shelf life, which affect their nutrition and commodity value, and pose a potential hazard to human health. In this review, we summarized the mechanism of lipid oxidation, the relationship between oil oxidation & deterioration and senescence, influencing factors, as well as controlling methods for nut products oxidation. In addition, we also made prospects on the controlling methods against oil oxidation & deterioration about nut products industrials in future, and expected to provide some information for the betterquality maintenance of nut products. © 2017, Editorial Office of Journal of CIFST. All right reserved.
This study was about the influence on Dendrobium candidum's postharvest quality during ice-temperature storage, in order to exploring an effective method that can extend the storage life and maintain the storage quality of Dendrobium candidum. To study the influence on Dendrobium candidum's postharvest quality during ice-temperature storage, the freezing curve, the total polysaccharides and water-soluble polysaccharides, cellulose content, chlorophyll content, water content and the activity of phenylalanine ammonialyase were measured. The result is that the freezing point of Dendrobium candidum was (-2.3 ± 0.3) ℃, and ice-temperature storage (-2 ℃) can effectively inhibits the transpiration and the synthesis of cellulose, maintain the content of polysaccharides and chlorophyll of Dendrobium candidum, ultimately extend the storage life and maintain the storage quality. © 2017, Editorial Office of Journal of CIFST. All right reserved.
Polyvinyl alcohol (PVA), sodium alginate (SA) and chitosan (CHI) are all biodegradable materials with excellent film-forming properties. This study prepared bilayer films with PVA-CHI film as the outer layer and SA film as the inner layer. Fuzzy comprehensive evaluation was used to study the effects of the SA film formula where nano-cellulose, surfactant, calcium chloride and anti-bacterial agents were added. The performance of the bilayer films was evaluated considering water solubility, water barrier, mechanical and antibacterial properties. And the effects of the coatings on qualities of shell eggs were investigated. The results demonstrated that the bilayer film possessed lower water vapor permeability (WVP) than the single-layer one, and water droplet was more difficult to spread on bilayer film. Increasing the content of SA significantly increased (p ≤ 0.05) the mechanical properties of bilayer film, and the tensile strength (TS) increased 1.8 times when the SA content increased from 1 to 2%. Calcium chloride decreased the film solubility, and Tween 80 reduced the surface tension of the film-forming solution. Moreover, ethyl paraben sodium significantly increased the antibacterial activity of the bilayer film against E.coli and L. innocua, but had negative impact on TS and WVP. According to the orthogonal test L9 (3 4), the optimal formula of SA layer was: SA 1.25%, calcium chloride 0.75%, Tween 80 0.175%, and ethyl paraben sodium 0.125%. In addition, coatings reduced weight loss, and maintained Haugh unit and yolk index of shell eggs during 15 days of storage at 25 °C, especially bilayer coating.
Fresh walnut kernel was considered as delicious and nutritious, but hard to storage, it make an obstacles for selling and storage. The objective of this study was investigated a safe and highly efficient method for walnut preservation. The "WEN 185" thin-shell walnut which is the major production walnut varieties in Xinjiang province was used as test materials. Effects of different concentration (40 mg/L and 80 mg/L) chlorine dioxide (ClO2) treatment and different packing methods(Aluminum foil-heat sealing and aluminum foil-vacuum package) on storage quality and lipid oxidization enzyme activity of Fresh Walnut was explored. The results revealed that vacuum packing combined with low concentration of chlorine dioxide (40 mg/L) treatment could restrain decay rate, respiration intensity and browning of fresh walnut kernel effectively. The storage quality of walnut kernel was effectively preserved. The change of the nutrient in walnut kernel was analyzed. It was found the consumption of protein and sugar content was decreased significantly. Meanwhile the increase of acid value and peroxide value were delayed, it cause the oxidation decomposition of unsaturated fatty acid which is the main beneficial components of walnut kernel was significantly reduced. The peaks of fat oxidation related enzyme activity (SOD, CAT) was postponed 10 d, the activity of lipoxygenase was effectively reduced. It indicted that the production of harmful materials such as free radicals and superoxide were inhibited. The regulation pathway of fresh walnut kernel quality keep with enzyme activity was expounded. © 2017, Editorial Office of Journal of CIFST. All right reserved.
Background: Reducing spoilage and prolonging the shelf-life of food materials are critically important in food industry. Among many available preservatives, ethanol has been widely used for the storage of fruits and vegetables. Although a few ethanol emitters as an antimicrobial packaging are available, these ethanol emitters are high volatility, uncontrolled release, and other disadvantages, the practical applications are limited. Results: A novel ethanol gel with controlled release rate was prepared by gelatification reaction between ethanol and sodium stearate to overcome the disadvantage of conventional ethanol emitters. Hardness, adhesiveness and cohesiveness of developed ethanol gels increased whereas the springiness decreased along with the increase in sodium stearate concentration. The release rate of ethanol in the gels was controlled by the concentration of sodium stearate, in which a first-order release kinetic was observed. The release rate constant (k) of the gels with 12.5, 37.5, 62.5 g kg(-1) of sodium stearate was 0.58 ± 0.029 h(-1) , 0.49 ± 0.035 h(-1) and 0.41 ± 0.021 h(-1) , respectively, at 25 °C. The application of the controlled release ethanol emitter on storage of Chinese bayberry fruit demonstrated its ability to reduce the decay rate, maintain firmness, and inhibit the increased of MDA content at 4 °C. Conclusion: In terms of practical applications, the proper sodium stearate content can be selected according to the storage period, in order to achieve the precise storage goals. Therefore, the ethanol emitter has a potential application prospect as an active packaging in Chinese bayberry fruit as well as other perishable products.
Mulberry (Moms alba L.) was considered as delicious and nutritious fruit, but hard to storage, it make an obstacles for selling and deep processing. The objective of this study was to explore corruption control techniques and mechanisms for postharvest mulberry. "Dashi" mulberry was used as test materials, the effects of exposure to different concentrations ozone on postharvest physiology quality were revealed. Preservation mechanism and pathways were been explored through the ways of cell ultrastructure and cell wall components. The results revealed that mulberry fruits exposed to suitable concentration (4.29 mg/m³) ozone reduced soluble solid loss, decay ratio, respiration intensity, soften, and also beneficial in keeping the fruit color and commercial. The investigate of ultrastructural observation and cell wall material declared that ozone treated could induce epidermis stoma shrink, inhibit bacteria invasion, reduce water transpiration, significantly delay the decomposition of the cell wall and autolysis epidermal tissue degradation. © 2016, Editorial Office of Journal of CIFST. All right reserved.
Food packaging material is important for food safety. The development and innovation of fresh food packaging technology is in agreement with the concept of modern consumption, and also provide additional value for the industrial postharvest agricultural products. The demand for packaging materials is no longer limited to ordinary, but gradually changed into safe, eco-friendly, health and efficiency. Conventional packing, antimicrobial packaging, edible films, nano-composite materials and their applications in the field of fresh food preservation are reviewed. Additionally, research progresses in recent years, particularly studies about packing materials are summarized in detail. Finally, the current problems and future research of fresh food packaging materials are discussed. © 2015, Chinese Institute of Food Science and Technology. All right reserved.
Blueberries are now the second most economically important soft fruit. However, they are highly perishable and susceptible to rapid spoilage. One of the main factors limiting postharvest life of blueberries is softening. The changes of fruit firmness, cell wall degrading enzymes and cell wall composition of ‘Brilliant’ blueberry (Vaccinium ashei cv. Brilliant) were investigated in this study. The results showed fruit firmness declined concomitantly with the increase of the content of water soluble pectin (WSP) during storage paralleled by a decreasing amount of sodium carbonate soluble pectin (SSP), cellulose and hemicellulose. Blueberries stored at low temperature (5 °C) maintained higher fruit firmness than those stored at 10 °C, which was due to the lower WSP content and higher contents of SSP, cellulose and hemicellulose. Meanwhile, the lower activities of cell wall degrading enzymes such as polygalacturonase, cellulase, β-galactosidase and α-mannosidase in blueberries at 5 °C were associated with greater fruit firmness and lower WSP content as compared to those in fruit stored at 10 °C.
Carvacrol was embedded in β-cyclodextrin by the method of supersaturated solution in this papre. The inclusion conditions were optimized through the orthogonal experiment, and the results were as follows: the inclusion core/ wall ratio, 1:8; inclusion time, 2h; the temperature, 60℃. The inclusion rate reached 61.89% under the optimal condition. Furthermore, the formation of inclusion complex was confirmed by fluorescence spectrum and scanning electron microscopy. The release experiment showed that the release of carvacrol from the carvacrol-β-CD inclusion complex was influenced by the temperature and humidity. In addition, the slowly released carvacrol showed certain antimicrobial activity to Penicillium citrinum, and the suitable concentration was 0.05 gram. ©, 2015, Chinese Institute of Food Science and Technology. All right reserved.
Accumulation of advanced lipoxidation end products (ALEs) has been implicated in many chronic and degenerative diseases. In this study, we evaluated the effects of malondialdehyde (MDA), trans-2-heptenal, and trans,trans-2,4-heptadienal on the properties of native proteins and the formation of bovine serum albumin (BSA)-ALEs. Incubation of BSA with these aldehydes resulted in modification of Lys and Arg residues, conformational changes, and formation of colored, fluorescent, lipofuscin-like pigments (exhibiting strong lipofuscin-like fluorescence for MDA-BSA, but much weaker fluorescence for the other two aldehyde-BSA molecules). Moreover, the generated BSA-aldehyde complexes exhibited ultraviolet-visible (UV-Vis) absorption, i.e., the MDA-BSA adduct exhibited increased UV-Vis absorbance at 290 and 400nm, while the other two aldehyde-BSA molecules exhibited increased UV-Vis absorbance at 280 and 300-350nm, respectively, and cross-linking, similar to the characteristics of Maillard reaction products. The formation of aggregates was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The variables measured above showed that heptadienal-BSA and heptenal-BSA samples exhibited both similarities and differences from MDA-BSA samples. These results provide insights into the characteristics and formation of ALEs in terms of their biochemical interactions and applications in food science.
Lipofuscin-like pigments (LFLP) are considered a hallmalk of aging. The intracellular LFLP formation rate is negatively correlated with the life expectancy of cell. In food quality, increase of LFLP not only affects the appearance,but also causes loss of nutritional value. The accumulation of LFLP increased during storage of all walnuts. LFLP fluorescent intensities of walnuts with 4, 6, 12 and 16% moistures at the end of storage were 8.1, 4.8, 4.3 and 2.8 times of those at the beginning, respectively. The LFLP accumulation of walnuts with high moisture was found to be negatively correlated with soluble sugars and DPPH quenching rate, but positively correlated with the content of hydroxy methyl furaldehyde (HMF). While the LFLP accumulation of walnuts with low moisture had a strong positive correlation with anisidine value, it exhibited high negative correlations with acid phosphatase activity, DPPH quenching rate, and tocopherol content. In walnuts with low initial moisture, lipoxidation products increased makedly during storage and these products might provide the source for LFLP accumulation. On the other hand, in walnuts with high initial moisture, reducing sugars derived from the hydrolysis of soluble sugars might play an important role in initiating the Maillard-like reaction leading to the LFLP accumulation.
Based on response surface methodology, the conditions of synthetizing Conjugated Linoleic Acids (CLA) by alkali isomerization technique were optimized with the linoleic acid in Carya cathayensis Sarg. oil as the material. Factors of reaction time, temperature, and the weight ratio of the linoleic acid material to KOH were selected to investigate the effects on the concentration of CLA based on the single factor experiment. The isomerization process of linoleic acid was optimized by response surface methodology, and the regression model was established with the concentration of CLA as the response value. The results show that the optimum process parameters were: reaction time 4 h, reaction temperature 174 ℃, the weight ratio of the linoleic acid material to KOH 1.87, propylene glycol to linoleic acid weight rate at 2. Under the conditions the mass fraction of CLA was 62.87%, and theoretical mass fraction was 64.72%, the error was 2.86%.
Sensory quality of litchi fruit is closely related to the appearance, flavor and nutritional quality. Principle component analysis (PCA) and multi-linear regression analysis (MLR) were performed to select the crucial quality factors in determining litchi sensory quality, and then a mathematical model was established to evaluate the litchi quality. Sensory evaluation value was conducted by a trained panel while sixteen instrumental quality parameters were used, including color (L *, a * and b *), single fruit weight (SFW), total soluble solids (TSS), pH, crude protein (CP), vitamin C (Vc), titratable acid (TA), glucose, fructose, sucrose, malic acid (MA), tartaric, edible rate (ER), and juice yield (JY). The PCA result demonstrated that six principle components exhibited high relationship with sweet and sour degrees, color, ER, TSS, Vc, CA and JY, which accounted for 82.359% of the original variables, and MLR results indicated that the crucial quality parameters were SFW, TA, a *, and ER. The predicted model was established in which validity QLOO2=0.603>0.5 in leave-one-out cross validation. Cluster analysis was used to select the cultivars suitable for eating quality which can provided a guide for litchi production and breeding.
In order to investigate the effects of Silicate gel controlled release AITC on the preservation of strawberry fruits, the effect of controlled and non-controlled release AITC treatment on the postharvest quality of strawberry was conducted. Strawberry fruits (Fragaria ananassa Duch. cv. Toyonoka) were stored at 5°C for 15 days under the treatment of 10-5 AITC and 0.1 g Silicate gel controlled release AITC respectively. The results indicated that both controlled and non-controlled release AITC can reduce rot index, inhibited the respiratory intensity and the increase of conductivity, which maintained high firmness VC and total polyphenol content in strawberry during storage. Besides, which also reduced decrease rate of titratable acid. This demonstrated controlled and non-controlled release AITC treatment both have good effects of postharvest strawberry preservation. Which can prolong the postharvest life of strawberry and maintain its high quality. Compared with non -controlled release AITC, Silicate gel controlled release AITC is more convenient meanwhile its can maintain higher sensory quality and nutrient composition than non-control released AITC.
In order to explore the effect of epicuticular wax on postharvest blueberry fruits, the structure of epicuticular wax and its effect on softening of postharvest fruits were investigated. The results showed that, blueberry fruits will accelerate senescence more easily without epicuticular wax. Epicuticular wax not only reduced the decay rate and weight loss rate, but also significantly decreased the activities of pectin methylesterase (PME), polygalacturonase (PG) and cellulose. Epicuticular wax was also found to delay the depolymerization of propectin and cellulose to inhibit the increase of water soluble pectin (WSP), and to maintain fruit firmness. From the above results, it could be concluded that epicuticular wax of blueberry fruits was closely related to softening.
The test in the paper has selected walnut samples from Ling'an Mountain in Zhejiang Province for experiments to evaluate the composition and relative percentage of fatty acid in walnuts (Carya cathayensis Sarg.), and figure out the pattern of oxidation of four kinds of important fatty acid and changes in antioxidant activity during walnut processing. The results showed that walnut contains 13 kinds of fatty acids found at present, of which including oleic acid (C18:1), linoleic acid (C18:2), palmitic acid (C16:0) and linolenic acid (C18:3) as the four most important fatty acids in walnut. These four main fatty acids showed a slow downward trend in processing, in which linoleic acid and linolenic acid have declined the most in the braising stage; while palmitic acid decreased dramatically in the first stage of sautéing. The results showed that braising stage has the greatest impact on antioxidant ability. The lipid droplets of walnuts cells ruptured after braising and then the lipid droplets came to spread and melt during the processing. The data indicated that oxidation of fatty acid occurs incessantly during the four stages of processing and long time of high temperature treatment promoted the oxidation of fatty acid and meanwhile decreased the antioxidant activity with the cell structural of walnut being destructed.
Minimally processed water bamboo shoot (WBS) lignifies and deteriorates rapidly at room temperature, which limits greatly its marketability. This study was to investigate the effect of modified atmosphere packaging (MAP) on the sensory quality index, lignin formation, production of radical oxygen species (ROS) and activities of scavenging enzymes, membrane integrity and energy status of minimally processed WBS when packaged with or without the sealed low-density polyethylene (LDPE) bags, and then stored at 20[degree sign]C for 9 days or 2[degree sign]C for 60 days. The sensory quality of minimally processed WBS decreased quickly after 6 days of storage at 20[degree sign]C. Low temperature storage maintained a higher sensory quality index within the first 30 days, but exhibited higher contents of lignin and hydrogen peroxide (H2O2) as compared with non-MAP shoots at 20[degree sign]C. Combined MAP and low temperature storage not only maintained good sensory quality after 30 days, but also reduced significantly the increases in lignin content, superoxide anion (O2.-) production rate, H2O2 content and membrane permeability, maintained high activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and reduced the increase in activities of lipase, phospholipase D (PLD) and lipoxygenase (LOX). Furthermore, the minimally processed WBS under MAP condition exhibited higher energy charge (EC) and lower adenosine monophosphate (AMP) content by the end of storage (60 days) at 2[degree sign]C than those without MAP or stored for 9 days at 20[degree sign]C. These results indicated that MAP in combination with low temperature storage reduced lignification of minimally processed WBS, which was closely associated with maintenance of energy status and enhanced activities of antioxidant enzymes, as well as reduced alleviation of membrane damage caused by ROS.
Vacuum cooling is a rapid cooling technique extensively used for cooling some agricultural and food products. The vacuum cooling technology is now gradually applied to the precooling treatment of agricultural products due to the advantages of quick cooling, easy operation, no constraint of packing containers, and energy savings. Consumption of Agaricus bisporus has increased substantially because of its delicacy, flavor and nutritional value. Agaricus bisporus is an excellent source of several essential amino acids, vitamins (B2, niacin, and folates), and minerals (potassium, phosphorus, zinc, and copper). Agaricus bisporus has a short shelf life of 3-4 days compared to most vegetables at ambient temperatures because it has no cuticle to protect it from physical or microbial attack or water loss. Loss of quality is caused by morphological changes due to maturation, discoloration, changes in texture and flavor, and losses of nutrients. Textural changes of fruits are accompanied by loss of neutral sugars, solubilization and depolymerization of the polysaccharides of the cell wall, and rearrangements of their associations, as the result of the combined action of several cell wall-modifying enzymes, acting in both pectic and hemicellulosic fractions. Recent studies on the structure of the plant cell wall have disclosed a large number and type of biochemical linkages between the components. Such linkages are potential targets for enzymatic action and draw attention to the putative involvement of several members of enzymes able to act and modify its structure in a developmental and coordinated way. The objective of this study was to determine the effect of vacuum cooling treatment on cell wall compositional changes and ultrastructure in fresh mushrooms during 15 d of post-harvest storage at 4°C. In this study, we investigated the change of cellulose content, cellulose activity, propectin content, WSP content, and the PG activity of Agaricus bisporus before and after vacuum cooling. We also studied changes in those properties during storage. The results showed that vacuum cooling treatment could retard the increase of cellulose activity and PG activity and slow down the reduction of cellulose content and propectin content. At the end of storage, the contents of cellulose and propectin of Agaricus bisporus without vacuum cooling treatment were decreased by an average of 58.0% and 62.07%, respectively. The significant difference was found between the Agaricus bisporus without and with vacuum cooling treatment (P<0.05). No sign of damage could be observed as a result of vacuum cooling the Agaricus bisporus. During the storage, the Agaricus bisporus with vacuum cooling treatment retained its structure better than without vacuum cooling.
In the experiment, we studied the extraction method of lipofuscin-like pigments from Chinese walnuts (carya cathayensis), explored their feature fluorescence spectrum of lipofuscin-like pigments, and found out their suitable pretreatment of samples before extraction. And then on this basis the single factor test and orthogonal experiment L9(34) design methods were applied to study the influence of the variables on the lipofuscin-like pigments such as extraction mode, temperature and time, as well as PH of extraction solvent. The results showed that, the highest extraction rate of lipofuscin-like pigments could be gained in the conditions (extraction solvent with the proportion of chloroform: methanol: phosphate buffer (2:1:1), extraction time of 2.0 h, extraction temperature of 50°C and extraction solution of pH 6.0) after oil removal pretreatment with ether.
Objective: To investigate effects of different frozen storage temperatures and salt solutions on protein denaturation and ultrastructure of channel catfish fillet. Methods: channel catfish fillet were treated for 2 min with or without salt solutions, and then frozen into -18, -30 and -50°C for 15 months. Results: channel catfish fillet exhibited lower contents of fat and protein, pH, extractable protein nitrogen value, and Ca2+-ATPase activity, and higher TVB-N value and K value after storages at -18, -30 and -50°C for 15 months than those were before frozen storage, which indicated that channel catfish fillet had a decrease in nutritive quality and the protein denaturated. Frozen storage temperature was lower, the degree of protein denaturation lighter and cell ultrastructure of tissues better. In addition, soaking cryoprotectants in fillet maintained nutritive quality and reduced the protein denaturation. Conclusion: frozen storage temperatures markedly affect the protein denaturation and ultrastructure, and cryoprotectants effectively eased the protein denaturation of channel catfish fillet when stored at frozen temperatures.
A novel oxygen scavenger using iron nanoparticle was produced and evaluated as a potential oxygen scavenger. Iron nanoparticle was prepared by liquid phase reduction method in microemulsion systems. The absorption capacity of different kinds of oxygen scavengers was measured as a function of time, and the absorption rate constant was evaluated at 25°C. The absorption kinetic analysis showed that the absorption process followed a first-order reaction. The absorption rate constant of nanosised and conventional oxygen scavenger were 0.45±0.044h(-1) and 0.05±0.006h(-1), respectively. Successful application of the nanosised oxygen scavenger on roasted sunflower seed and walnut demonstrated its ability to inhibit lipid oxidation in lipid-containing food. Roasted nut treated with nanosised oxygen scavenger possessed the lowest PV and AnV in all treatments after 120days of storage. Therefore, it has the potential for broad application as an active packaging in a variety of oxygen-sensitive foods.
Shrimp is a very perishable product and postmortem changes occur rapidly. Sulfiting agents were once and are still widely used as a preservative in the shrimp industry. However, the application of sulfite in shrimp may pose a risk to human health. Thus development of a natural preservative as a sulfite alternative to extend the shelf life of Pacific white shrimp is urgently needed. The effects of cinnamaldehyde essential oil (1 and 5 g kg(-1) ) on the shelf life of Pacific white shrimp stored at 4 °C were investigated. As the concentration of cinnamaldehyde increased, residual polyphenoloxidase (PPO) enzyme activity decreased. Kinetic analysis showed that cinnamaldehyde was a noncompetitive inhibitor for the oxidation of L-DOPA (L-3,4-dihydroxyphenylalanine) by PPO of Pacific white shrimp. Based on this study, shrimp treated with 5 g kg(-1) cinnamaldehyde possessed the lowest aerobic plate count, total volatile basic nitrogen, and pH values in all treatments after 10 days of storage. According to the results of L*, cinnamaldehyde showed inhibitory activity toward the formation of melanosis. Treatment with cinnamaldehyde could improve the sensory properties and extend the shelf life of Pacific white shrimp to 8 days. Therefore, cinnamaldehyde could be used as a promising natural preservative for inhibiting melanosis and preventing the growth of microbes during the chilled storage of Pacific white shrimp.
The effects of eight natural compounds on quality and shelf life of Pacific white shrimps was investigated. Cinnamaldehyde exhibited both antimicrobial activity and inhibitory ability against polyphenol oxidase (PPO) activity to maintain the quality of the Pacific white shrimp during storage. The kinetic analysis showed that cinnamaldehyde was a noncompetitive inhibitor for PPO of the Pacific white shrimp. The combined preservative was optimized using orthogonal experiment and then the optimal combination was as follows: 0.10% cinnamaldehyde, 0.05% phytic acid and 0.50% sodium alginate. The aerobic plate counts (APC), total volatile bases nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) assay and sensory analyses were used to investigate the change in the quality of the Pacific white shrimps after applications of different treatments. Based on these studies, shrimps treated with the combined preservative exhibited the lowest APC, TVB-N, and TBARS value among the all treatments by the end of storage. The combined preservative could improve the sensory properties and prolong the shelf life of the Pacific white shrimps to 8-10 days.

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Affiliations

Zhejiang Academy of Agricultural Sciences
Department
  • Department of Food Science

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