2020, 38(4):1-9. DOI: 10.3969/j.issn.2095-6002.2020.04.001
Abstract:Rice is one of the most important staple foods in China, which is usually cooked as fresh food. And it has great theoretical and practical significance to study the relationship between components and its cooking quality. Protein is the second largest storage substance in the endosperm of rice seed, which is next only to starch, and is one of the important indexes to determine the quality of rice. The main component of rice protein is glutelin, accounting for about 65% to 80%. The other three proteins are albumin, prolaminand globulin. Rice protein is considered as one of the high quality plant proteins. Compared with soybean protein and wheat protein, the structure and properties of rice protein have not been systemically and deeply studied. And the correlation of rice protein and its edible quality is even more insufficient. In this paper, research progress and achievements of rice protein composition, structure, and its influence on the cooking quality were reviewed and summarized, which might help to find the deficiency and academic trend of studies on rice protein.
2020, 38(4):10-20. DOI: 10.3969/j.issn.2095-6002.2020.04.002
Abstract:As an economic fruit which is homology of medicine and food, Lycium barbarum is rich in polysaccharides, carotenoids, flavonoids, betaine, taurine and other functional components. It also serves many functions such as enhancing immune regulation, anti-aging, preventing cancer and tumor growth, reducing blood glucose and lipid level, etc. And the demand of Lycium barbarum related products is increasing. The growth character of Lycium barbarum belongs to infinite inflorescence, and the ripening period of fruit is longer from June to October. However, Lycium barbarum fruit softens rapidly in the later stage of ripening, which leads to vulnerable to mechanical damage and pathogen infection, limiting the storage and transportation of fruit. Therefore, in order to reduce the loss of Lycium barbarum fruit and meet the needs of consumers for health care function, it is necessary to carry out deep processing of Lycium barbarum during ripening period. This paper expounded the main nutritional value and health care effect of Lycium barbarum, introduced the current situation of deep processing products and related technical equipments of Lycium barbarum, and pointed out the development prospect, direction and challenges of deep processing products of Lycium barbarum, which provided theoretical reference for the development of deep processing industry of Lycium barbarum.
2020, 38(4):21-26. DOI: 10.3969/j.issn.2095-6002.2020.04.003
Abstract:Obesity is one of the worldwide concerned chronic diseases, which is a risk factor of cardiovascular and cerebrovascular diseases, cancer and other diseases. It has become the most important health problem threatening human. Most of the existing weight-loss drugs or methods have the disadvantages of great toxic and side effects and easy to rebound. Therefore, it is of great significance to seek safe and effective drugs or methods to intervene obesity. Natural plant extracts including anthocyanins have effective intervention on obesity with little side effects. Lycium ruthenicum Murr. is one of the newly discovered edible plant resources in recent years. It has a variety of biological activities, such as reducing blood lipid, anti-oxidation, anti-mutation, anti-cancer, anti-inflammation, improving immunity and so on. Differing with others from common fruits and vegetables, the characteristic structure of anthocyanins from Lycium ruthenicum Murr. is containing parent nucleus of petunia and aromatic acid acylation. And the total content of the anthocyanins is much higher than other colored fruits. In this paper, the research progress of the effect of anthocyanins in Lycium ruthenicum Murr. on intervention of obesity was reviewed by summarizing the relevant references, which provided theoretical references for the development and utilization of Lycium ruthenicum Murr..
2020, 38(4):27-36, 62. DOI: 10.3969/j.issn.2095-6002.2020.04.004
Abstract:In order to study the effects of different cutting direction on the quality of purple cabbages, the apparent color, browning degree, contents of soluble solids, phenolic compounds and anthocyanins, and flavor profiles of freshly transverse or longitudinal cutting purple cabbages before and after storage were compared. After storage for 9 days, the results showed that Land aof fresh cut purple cabbages were decreased, band browning index were increased, the soluble solids content was decreased by 0.27-0.33Brix, and contents of total phenol and anthocyanins were increased by 2.69-2.78mg/g and 0.06-0.11mg/g, respectively. Longitudinal cutting could slow down the browning and maintain the phenolic compounds such as catechin, chlorogenic acid, caffeic acid, ferulic acid and quinic acid. In addition, the nitrogen oxides in purple cabbage was increased after storage analyzed by electronic nose and volatile matter, and allyl isothiocyanate in transverse cutting samples was increased than that in longitudinal cutting samples, which led to undesirable odor production. In conclusion, longitudinal cutting could efficiently slow down the surface browning and maintain the phenolic substances and flavor quality of purple cabbages. The results could provide theoretical references for improving the quality and extending the shelf life of fresh-cut purple cabbage.
2020, 38(4):37-45. DOI: 10.3969/j.issn.2095-6002.2020.04.005
Abstract:In order to reveal the main composition of endophytic bacterial communities in nectarine and Kuqa apricot, and screen and verify the potential pathogenic bacteria, then provide the foundation for the research of storage, freshness, and prevention of soft rot disease, the endophytic bacterial communities in postharvest nectarine and Kuqa apricot in Xinjiang were analyzed by high-throughput sequencing. The pathogenic bacteria were screened by traditional isolation and culture methods, then identified based on 16S rDNA sequences analysis. The pathogenicity of strains was tested and identified by in vitro inoculation method and re-isolation method. The results showed that endophytic bacterial communities in nectarine and Kuqa apricot contained 128 operational taxonomic units (OTUs), involving 117 genera of 9 phylums. Proteobacteria was absolute dominant phyla followed by Firmicutes and Bacteroides. At the genus level, Pantoea, Bacillus, Pseudomonas and Bacteroides were the dominant microflora in nectarine, while Gluconobacter, Pantoea, Christensenella and Prevotella were the dominant population in Kuqa apricot. A potential pathogenic bacteria named XAAS-P1 related to soft rot disease was obtained, which was classified in Pantoea by phylogenetic tree construction of 16S rDNA sequence. It exerted the ability to cause the postharvest decay of nectarine and Kuqa apricot, which had consistent symptoms with natural soft rot. After 4 days inoculation, the incidence of decay was 100%, and the decay appeared 1 days earlier compared with the negative control group. Results of re-isolation and identification showed that strain XAAS-P1 was the absolutely dominant bacteria in lesion, which proved that strain XAAS-P1 was the pathogenic bacteria caused the postharvest decay of nectarine and Kuqa apricot. The study indicated that diversity of endophytic bacteria in nectarine and Kuqa apricot was rich, and the endophytic bacterium, Pantoea sp. XAAS-P1 could lead to the postharvest decay of nectarine and Kuqa apricot.
2020, 38(4):46-53. DOI: 10.3969/j.issn.2095-6002.2020.04.006
Abstract:This study took instant Lentinus edodes (L.edodes) soups as the research object to analyze the effects of steam reheating and microwave reheating methods on the flavor characteristics of L.edodes soups using electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS). The results from electronic nose showed that the odor characteristics of L.edodes soups after reheating changed significantly (P<0.05). By GC-IMS analysis, 56 volatiles compounds including some dimers of flavor compounds were both identified in L.edodes soups before and after reheating. And the varieties of flavor compounds were same, but the contents were significantly varied. The contents of ocimene, octanal and its dimer, heptanal and its dimer, 2-cyclohexen-1-one, 2-furfural and its dimer, pentanal and its dimer and 2-methylpropanal in microwave reheating L.edodes soups were higher than those of steam reheated and unheated L.edodes soups. The contents of dimethyl trisulfide, p-cresol, dimethyl disulfide, 5-methyl-2-furfural, 1-hexanol and its dimer in steam reheating L.edodes soups were higher than those of microwave reheated and unheated L.edodes soups. Collectively, the reheating treatment had a greater influence on the volatile flavor substances of the L.edodes soups, and the contents of the volatile flavor substances in the reheated L.edodes soups were higher.
2020, 38(4):54-62. DOI: 10.3969/j.issn.2095-6002.2020.04.007
Abstract:In order to screen bioactive peptides against SARS-CoV-2 from food raw materials, Mizuhopecten yessoensis myosin was selected as the target sequence, which was enzymatically digested in silico, and then the toxicity and bioactivity of the peptides were predicted. The non-toxicity peptides with activity scores exceeding 0.5 were selected, and SARS-CoV-S/ACE2 complex protein and COVID-19 Mpro hydrolase were selected as targets for molecular docking to identify their viral resistance. The molecular docking results showed that the peptide CSNAIPEL could bind to the two key amino acids GLN42 and GLU329 on the SARS-CoV-S/ACE2 complex protein, and the LibDock Score was 136.03. LPIY could not only combine with ASP38 and TYR491 on the SARS-CoV-S/ACE2 complex protein, but also potentially combine with THR24, THR25 and THR26 on COVID-19 Mpro, and the LibDock Score was 142.85 and 168.04 respectively. QRPR combined with THR24, THR25 and THR26 on the COVID-19 Mpro hydrolase crystal, and the LibDock Score was 154.93. In summary, peptides CSNAIPEL, LPIY and QRPR exhibited well anti-SARS-CoV-2 capability. This study could provide novel ideas for the development of new function foods of anti-SARS-CoV-2 in the future.
2020, 38(4):63-69, 78. DOI: 10.3969/j.issn.2095-6002.2020.04.008
Abstract:To study the effect of soybean peptides (SBP) on sleep in Drosophila, SBP was prepared by proteolytic separation of soybean. 20 days-old male Drosophilas melangogaster were selected and divided into 4 groups. The basic medium was used as a blank control group, and three experimental groups were cultured using basic medium containing 2,4 and 8mg/mL SBP, respectively. The sleep duration was detected by the VideoTrack animal behavior analysis system, and the effects of SBP on circadian clock genes (per, tim, clk, cyc) of Drosophila brain, sleep related genes of rate-limiting enzymes of neurotransmitter synthetase (gad, tph, gdh, hdc), and serotonin (5-HT) were analyzed. The results showed that SBP had the best effect on prolongation of sleep in a dose dependent manner on the second day of sleep monitoring. By stripping the head, the circadian clock genes (per, tim, clk, cyc) and neurotransmitter synthetase genes (gad, tph, gdh, hdc) were analyzed. It was found that SBP administration prolonged the sleep duration of Drosophila melanogaster by up-regulating the levels of tim and tph and increasing the secretion of 5-HT in the brain.
2020, 38(4):70-78. DOI: 10.3969/j.issn.2095-6002.2020.04.009
Abstract:Mono- and diacylglycerol lipase is broadly applied due to its unique substrate specificity. In this study, a putative mono- and diacylglycerol lipase gene prlip was identified from the genome of a food safety strain Penicillium roqueforti. The lipase PrLip was obtained by artificial synthesis strategy and constitutively expressed in Pichia pastoris X33. The lipolytic activity in the broth supernatant reached 22.26U/mL after fermentation for 60h at 30℃. The lipase PrLip was purified by anion exchange chromatography with the purity greater than 90%. The optimal reaction temperature and pH of PrLip were 45℃ and 7.0, respectively, and its thermostable half-life at 40℃ was about 6h. The lipase PrLip was characterized as a mono- and diacylglycerol lipase through hydrolysis and esterification. PrLip had a good tolerance against temperature and resistance to most surfactants, which is promising for potential application in industrial scale.
2020, 38(4):79-86, 110. DOI: 10.3969/j.issn.2095-6002.2020.04.010
Abstract:In order to explore the influence of D-fructose on the metabolism of Zygosaccharomyces rouxii, the effects of D-fructose on regulating the physiological characteristics and transcriptomics of Zygosaccharomyces rouxii were studied. The results showed that D-fructose addition significantly promoted (下转第110页)(上接第86页) cell growth and reduced the pH level of Zygosaccharomyces rouxii in yeast broth. In comparison with those in the control group, transcriptomics analysis revealed that there were 7469 differentially expressed genes in D-fructose regulating groups at 3d, 4611 differentially expressed genes at 5d, and 8611 differentially expressed genes at 7d, respectively. Compared with those in control group, GO enrichment analysis indicated that the differentially expressed genes related to molecular function, cellular component, and biological process in D-fructose regulating groups were significantly increased at 3,5 and 7d fermentation, respectively. The results of KEGG pathway analysis also indicated that fructose metabolism, secondary metabolism, and amino acid metabolism, which were closely related to metabolism of Zygosaccharomyces rouxii, were significantly varied after D-fructose addition. LC-MS/MS analysis showed that D-fructose treatment increased the acid contents at 3d, and after 5d fermentation, the main aroma substances such as ketones and esters were higher than that in the control group and the furanone content was 7.5 folds of control group. The difference among the metabolites was decreased at 7d. This study provided a theoretical basis for the understanding of the physiological characteristics and the molecular mechanism of aroma production in Zygosaccharomyces rouxii exposure to sugar stress.
2020, 38(4):87-93. DOI: 10.3969/j.issn.2095-6002.2020.04.011
Abstract:In order to improve the viscoelasticity, gel strength and thermal properties at high temperature of konjac glucomannan (KGM) gels, 0.2,0.5,0.8g, and 1.0g carboxyl cellulose nanocrystalline (CCNC) was used to mix with 1.5g KGM, and the composite hydrogel and blank control were prepared. The microstructure, characteristic functional groups and quality retention of CCNC/KGM hydrogels with different proportions were characterized by rheometer, scanning electron microscope, infrared spectroscopy and thermogravimetry analysis. The results showed that in a certain proportion range(≤0.8g), the viscosity of the system was higher with the increasing of CCNC proportion. Scanning electron microscopy showed that the gel network structure formed by synergistic interaction with KGM was rich in addition of 0.8g CCNC, and the gel weight loss of this compound ratio decreased by nearly 50% compared with that of pure KGM hydrogel at the molten state. The composite hydrogel exerted better thermal performance and retained some gel properties at high temperature. When the mass ratio of CCNC/KGM was about 0.8∶1.5, the viscoelasticity, gel strength and thermal properties at high temperature of the hydrogel were optimal.
2020, 38(4):94-102. DOI: 10.3969/j.issn.2095-6002.2020.04.012
Abstract:In this study, the physicochemical properties, component contents, microstructure and sensory qualities of the skeleton pulp of Lateolabrax japonicus obtained from different degrees of wet superfine grinding were analyzed. The physicochemical properties of fish skeleton pulp were measured using pH meter, ultraviolet spectrophotometer, colorimeter, texture analyzer, and laser particle size analyzer. Automatic amino acid analyzer was employed to detect the varieties and contents of amino acids. The microstructure was observed by scanning electron microscope. The results showed that, the particle sizes of samples larger than 100 mesh size were almost ranged from 50 to 100μm, while the particle sizes of samples less than or equal to 100 mesh size were mainly distributed between 100 and 300μm after wet superfine grinding at different degrees. In addition, pH value, ultraviolet absorbance, whiteness and bulk density were increased gradually with the increasing degree of wet superfine grinding. While the gel strength was first increased and then decreased. When the grinding degree increased from 20 mesh to more than 180 mesh, the content of calcium dissolution was increased from 151.23mg/kg to 270.06mg/kg, the collagen content was also slowly increased from 0.01% to 0.04%, the total content of amino acids was increased from 181.07ng/μL to 462.70ng/μL, the content of salt-soluble protein was increased from 6.95mg/g to 16.12mg/g,and the content of water-soluble protein was gradually increased from 2.15mg/g to 7.13mg/g. Furthermore, the scanning electron microscopy results revealed that samples with particles larger than 100 mesh were relatively smooth and uniform, while fish bones could be obviously observed in samples smaller than or equal to 100 mesh. The content of volatile basic nitrogen was in accordance with the relevant national standards. Combined with sensory evaluation, fish skeleton pulp above 100 mesh could be used as ingredients for fish powder, fish balls and other products, while fish skeleton pulp of less than or equal to 100 mesh might only be suitable for adding to products with large raw materials particle size such as soup packets, sauces and so on.
2020, 38(4):103-110. DOI: 10.3969/j.issn.2095-6002.2020.04.013
Abstract:In order to investigate the effect of sodium carbonate injection on tenderization and quality of air-dried beef, the pH, shear force, water content, water activity, yield and sensory quality of air-dried beef injected with different concentrations of sodium carbonate (0,0.25,0.30,0.35,0.40mol/L) were measured. The results showed that increasing the sodium carbonate concentration, the pH value, water content, water activity,yield and tenderness of air-dried beef were significantly elevated, the shear force was decreased. However, when sodium carbonate concentration was over 0.35mol/L, the sensory quality and chewiness of air-dried beef became worse and had a certain degree of alkali flavor. According to correlation analysis, there was a significant positive correlation between pH and tenderness, water content, water activity and yield of air-dried beef (P<0.01). Therefore, the effect of sodium carbonate injection on air-dried beef tenderness was mainly related to the change of pH in meat. The results indicated that sodium carbonate injection could effectively improve the edible quality of air-dried beef. This effect was best at the concentration of 0.35mol/L. And this condition, the shear force could be reduced by 33.67%, and the yield increased by 12.05% to 45.12%, and the change of pH value was the main reason for the improvement of air-dried beef tenderness and quality by sodium carbonate injection.
2020, 38(4):111-118. DOI: 10.3969/j.issn.2095-6002.2020.04.014
Abstract:In order to solve the problem of poor cooking resistance of quick-frozen rice dumpling, different types of cassava-based modified starch were blended with glutinous rice flour, and fresh rice dumpling and quick-frozen rice dumpling were taken as research objects to explore the effect of modified starch on the cooking resistance of rice dumplings. Four kinds of cassava modified starch were added to glutinous rice flour. The influence of modified starch on the gelatinization properties and boiling resistance of rice dumpling were compared to determine the type and addition amounts of modified starch by measuring the viscosity of rice dumpling powder and the hardness of rice dumpling. The results showed that the phosphate ester starch could improve the boiling resistance of the rice dumpling, and the hydroxypropyl distarch phosphate (3.3% hydroxypropyl content, medium degree of crosslinking) had more significant effect, while the hydroxypropyl starch (3.0% hydroxypropyl content) had better anti-retrogradation effect. When the two modified starches were added in combination, the round cooking resistance of rice dumplings can be improved, and at the same time, the anti-rejuvenation effect could be achieved. In the best formula, the mass ratio of hydroxypropyl distarch phosphate (3.3% hydroxypropyl content, medium degree of crosslinking), hydroxypropyl starch (3.0% hydroxypropyl content), glutinous rice flour was 8∶2∶90. Under these conditions, the resistance of rice dumplings was obviously improved. This conclusion not only provided a certain theoretical reference for the production and processing of quick-frozen rice dumpling, but also provided a basis for the application of modified starch in quick-frozen foods.
2020, 38(4):119-126. DOI: 10.3969/j.issn.2095-6002.2020.04.015
Abstract:Monascus spp. produces various secondary metabolites such as Monacolin K (MK) and Monascus pigments (MPs) during fermentation which were beneficial to human. In order to obtain a certain amount of MK and MPs at the same time, the solid-state fermentation (SSF) of Monascus MPs-7 on the rice substrate with the addition of different concentrations of soybean meal and soybean dregs was explored. The yield of the two metabolites were analyzed, and the influence mechanism of auxiliary material was also explored. The results showed that adding two kinds of auxiliary material as fermentation medium promoted the yield of MK. However, the yield of MPs was inhibited. When soybean meal addition was 15% (mass fraction), the production capacity of MK was the highest, but almost no MPs was produced. Addition of 15%(mass fraction) bean dregs as fermentation medium increased the yield of MK and in the meanwhile maintained a certain yield of MPs, and the cost was lower than that of soybean meal, which was more suitable as an auxiliary material added to the SSF of Monascus. The study showed that nitrogen content of the substrate could affect the accumulation of mycelium during the SSF of Monascus, thus affecting the production of secondary metabolites.