【Objective】 This study was performed to compare the differences of the protein hydrolysis and lipid productions during the quinoa fermentation with the different strains, so as to promote the development of quinoa added-value food by the fermentation .【Method】 Yeast, lactobacillus plantarum and the two mixed was used for the fermentation of quinoa, respectively. Proteolysis index, protein composition, lipid profile, the content of total free amino acid and free fatty acid were determined to evaluate which microbe had more advantages in the transformation of nutrients. 【Result】 The proteolysis index increased after the quinoa fermentation by different microbes, and albumin and globulin were mainly hydrolyzed among quinoa protein composition. There was a significant increase in the free amino acid of quinoa after fermentation, especially essential amino acids. The yeast-fermented quinoa was beneficial in gaining smaller molecular compounds that originated from protein hydrolysis. The free fatty acids content increased sharply after fermentation and met a proper ratio of SFA﹕MUFA﹕PUFA close to 1﹕1﹕1. The content of triglycerides and diglycerides were reduced, but the content of functional lipids (phospholipid) was increased. The quinoa with yeast fermentation was more favorable for the above transformation.【Conclusion】Quinoa fermented by yeast or lactobacillus plantarum could result in the hydrolysis of albumin and globulin into amino acids, especially the free essential amino acid levels increased significantly. The free fatty acids also increased after fermentation, wherein the triglyceride and diacylglycerol were reduced, and the content of phospholipid was improved. Quinoa with yeast fermentation had great potential in developing high-value nutritional products in the future.
【Objective】 In order to realize the authenticity discrimination of whole wheat flour, a high performance liquid chromatography (HPLC) detection and analysis method was established to explore the composition of alkylresorcinols (ARs) homologues in whole wheat flour and refined wheat flour. 【Method】 The HPLC conditions were investigated to determine five kinds of ARs homologues, including 5-heptadecylresorcinol (C17:0), 5-nonadecylresorcinol (C19:0), 5-heneicosylresorcino (C21:0), 5-tricosylresorcinol (C23:0) and 5-hentacosylresorcinol (C25:0), and then a methodological evaluation was processed. The contents and composition of ARs homologues in 47 samples, including whole wheat flour, refined wheat flour and wheat bran from home and abroad, were determined and conducted by heat map and principal component analysis (PCA).【Result】 The chromatographic column of ZORBAX SB-C18 (150 mm×4.6 mm, 5 μm, Agilent ) was used for gradient elution, and the column was eluted with 0.1% formic acid aqueous solution and 0.1% formic acid methanol solution. The ARs homologues could be effectively separated within 35 minutes under the UV detection wavelength at 280 nm. The column temperature was 35℃, and the flow rate was 0.5 mL·min-1with 20 μL injection. The peak shape of each homologue was symmetrical without interference, and the detected resolution was exactly. After methodological evaluation, the method was proved that it had good precision and sensitivity, the linear correlation coefficients of the standard curves were more than 0.999, the detection limit was 0.06-0.19 μg·mL -1, the recovery rate was 81.16%-112.92%, and the precision standard deviation was 0.02%-4.02%. Therefore, this method could be applied to determine the composition of ARs homologues. The composition of ARs homologues and total amount of ARs in different samples were found significantly after thermal cluster analysis (P<0.05). Among the ARs homologues of wheat flour samples, C21:0 was the highest, which accounted for 33%-61%; followed by C19:0, which accounted for 12%-44%; while the ratio of C17:0, C23:0 and C25:0 were the least. The content and abundance of ARs homologues in the whole wheat flour of United States and Canada were similar. The content of ARs homologues in abroad whole wheat flour was higher than the whole wheat flour in domestic. The composition of ARs homologues in domestic whole wheat flour was more abundant than refined wheat flour, except for individual refined wheat flour samples. The composition of homologous and total content of ARs in wheat bran F1 were significantly higher than whole wheat flour and refined wheat flour (P<0.05). The total content of ARs in wheat bran F1 was 1 795.78 μg·g-1, which was the most significantly difference compared with other samples (P<0.05). The results of PCA showed that the main difference index between wheat flour samples was the composition of ARs homologues. As the first principal component, the cumulative contribution rate was 98.40%. The relative dispersion between wheat bran and other wheat flour samples was the farthest, while the dispersion of Chinese refined wheat flour was the largest. Even the whole wheat flour of United States and Canada could nearly overlapped, the whole wheat flour and part of refined wheat flour of China could only partially overlapped.【Conclusion】 The HPLC method could be employed to effectively and rapidly quantify the ARs in whole wheat flour products. Moreover, the abundance of ARs homologues in whole wheat flour was better than that of ARs homologues in refined wheat flour under comparative analysis. In summary, the results could provide a theoretical basis for authenticity discrimination and quality control for whole wheat flour by exploring the composition of ARs homologues.
【Objective】A study was conducted to investigate effects of innoculation with a combination of Bacillus subtilis and Actinomucor elegans on the nutritional value and sensory characteristics of double-low rapeseed meal, and to evaluate the safety by in vivo experiment, so as to provide a theoretical basis for the utilization and deep development of rapeseed meal in the food industry. 【Method】The double-low rapeseed meal was used as the research object, and the static-state fermentation was used instead of the traditional stirring-state fermentation. The nutritional components (crude protein, water-soluble protein, small peptide, amino acid and tetramethylpyrazine) and anti-nutrient components (glucosinolates, phytic acid and crude fiber) of rapeseed meal after fermentation were determined, and then based on the odor and taste differences of electronic nose and electronic tongue, the correlation analysis and principal component analysis were used to evaluate the effect of static fermentation of mixed bacteria on quality of double-low rapeseed meal. The effects of fermented rapeseed meal on the growth performance of rats were studied preliminarily. These studies provided a theoretical basis for the application of fermented rapeseed meal products. 【Result】The results showed that soluble protein, peptides and total amino acid were increased by 96.7%, 281.48% and 19.58%, respectively after fermentation. Most rapeseed proteins were degraded into oligopeptides and amino acids with molecular weight between 500 Da and 108 Da. Tetramethylpyrazine, a new nutrient, was detected after fermentation. The concentration of tetramethylpyrazine reached 590 mg?kg-1 on the fifth day of fermentation. The contents of glucosinolates, phytic acid and crude fibers were decreased by 45.26%, 41.37% and 31.16%, respectively. The results of electronic nose and electronic tongue analysis showed that the flavor and taste of rapeseed meal changed significantly before and after fermentation, and the acid taste of rapeseed meal increased significantly after fermentation. Animal experiments showed that the addition of fermented rapeseed meal and other nitrogen instead of 25% soybean meal to rat diet could significantly increase the average daily intake and average daily weight gain of rats, and there was no damage to the kidney, thymus and liver of rats. 【Conclusion】The inoculant and fermentation method in the study could improve the nutritional value and flavor properties, and the fermented rapeseed meal could improve the growth performance of rats.
【Objective】 The effects of hot air-vacuum freeze combined with drying (HA-VFCD) on the physical properties and prebiotic activities of high-quality brittle dried longan were investigated in the present study, so as to provide a theoretical basis for the optimal industrialized energy-saving drying mode. 【Method】 In present study, the effect of HA-VFCD on the physicochemical and nutritional characteristics, such as moisture content, water activity, shrinkage rate, water rehydration ratio, total sugar and polysaccharide contents of brittle dried longan, were compared with that of individual hot air drying (HAD) and vacuum freeze drying (VFD) longan samples. The flavor substance changes and the energy consumption were also evaluated by GC-MS and ammeter, respectively. Furthermore, the dried longan was fermented by Lactobacillus plantarum and Lactobacillus acidophilus to investigate the content changes of viable bacteria, total sugar, reducing sugar and short-chain fatty acid, thus evaluating the effect of HA-VFCD on the in vitro prebiotic activities of longan. 【Result】 Longan dried by HA-VFCD showed significantly lower moisture content, water activity and shrinkage rate, but higher rehydration ratio, compared with the HAD counterparts. The content of total sugar, polysaccharide, and the types and amounts of volatile flavor of longan dried by HA-VFCD were lower than those of VFD samples, but higher than that of HAD counterparts. In addition, HA-VFCD process could save 12.16% of drying time and 25.40% of unit energy consumption, compared with VFD process. Both Lactobacillus plantarum and Lactobacillus acidophilus could increase the number of viable bacteria through fermentation of dried longan, which were used the total sugar in dried longan to produce short-chain fatty acids and to reduce the pH of fermentation broth. And the prebiotic activities of dried longan after fermentation were remarkably affected by the drying methods and the strain types of bacteria. After fermentation by the Lactobacillus plantarumfor 48 hours, the viable bacteria number of longan dried by HA-VFCD achieved the highest value of 12.40 lg cfu/mL, which was higher than that of HAD, VFD and fresh longan samples. After fermentation by the Lactobacillus acidophilus for 48 hours, the viable bacteria number of longan dried by HA-VFCD reached 11.84 lg cfu/mL, which was close to that of VFD samples, lower than HAD samples but higher than that of fresh longan. 【Conclusion】 The HA-VFCD process combined both the advantages of HAD and VFD, which could remarkably shorten the drying time, lower the energy consumption, and improve the drying efficiency and quality of dried longan.
【Objective】 The effects of protein supplements on the agronomic characters and quality of mushroom Agaricus bisporus were studied in the study, so as to provide a reference for the development, application and evaluation of Agaricus bisporus protein supplements. 【Method】 Four single protein raw materials were investigated as protein supplements, including soybean meal (SM), extruded soybean (ES), corn protein (CP) and Feather meal (FM). Commercial supplement (MCSubstradd?, MCS) was used as a positive control, and an unsupplemented compost was used as a blank control (CTL). The dosage of each supplement was determined based on their protein content and with a final protein dosage of 0.5% in the compost. Before casing, the supplements were thoroughly mixed with fresh Phase III compost. The mushroom strain was W192. Mushroom cultivation was carried out in accordance with the factory cultivation process mushroom room management. Three flush mushrooms were harvested, and yield, diameter and thickness of pileus, weight of single mushroom, and hardness characters were determined with reference to UPOV. Protein content was determined by kjeldahl method, and amino acid content was determined by amino acid analyzer. 【Result】 SM, ES and CP could effectively increase the mushroom yield. Among the four experimental groups, CP group manifested the highest total yield of 35.24 kg?m-2 with the yield increasing rate of 24.26% towards CTL group. Its biological efficiency was 105.98%, which was significantly higher than that of the other three assayed groups and CTL group, and slightly higher than that of MCS group. CP group demonstrated considerably high sustained-release effect with three flush yield of 48.72%, 35.09%, 16.19%, respectively, which was close to that of MCS group. Economic benefit analysis showed that CP group demonstrated the highest increasing benefit of 785 yuan in one ton compost. ES group showed high yield with significantly high hardness character in the first two flush. All the five protein supplements could significantly enhance the protein content in the fruiting bodies in all the three flush. In all the groups, the three amino acids with the highest content were Glu, Val, and Asp. FM and CP could enhance the content of delicious amino acids, which raised the flavor and taste of mushrooms. 【Conclusion】 Protein supplements could effectively increase mushroom yield, and had specific effects on the agronomic characters and qualities of fruiting bodies. Focusing on specific advantages of various additives, developing mixed and sustained-release supplements could achieve high quality and high yield of A. bisporus, which was the research direction of mushroom supplements in the future.
