Total Amino Acid Content Research Articles

The Application of Moringa oleifera Leaf Meal and Its Fermentation Products in the Diet of Megalobrama amblycephala Juveniles

This study assessed the potential applicability of Moringa oleifera leaf meal (MO) and fermented Moringa oleifera leaf meal (FMO) as feed supplements for aquatic animals. Five experimental diets, including the basal diet (control), 2.2% and 4.4% MO-supplemented diets (MO2 and MO4), and 2.2% and 4.4% FMO-supplemented diets (FMO2 and FMO4), were prepared for feeding Megalobrama amblycephala juveniles. After the eight-week feeding trial, the growth performance, muscle nutritional composition, plasma and hepatic biochemistry indicators were measured. The results demonstrated that MO and FMO had no detrimental effects on the growth performance of M. amblycephala juveniles. The muscle crude protein, crude lipid, and total free amino acids contents were significantly enhanced in the FMO4 group (p < 0.05). The liver acetyl-CoA carboxylase α mRNA level was significantly increased and the lipoprotein lipase mRNA level was markedly reduced in the FMO4 group (p < 0.05). Therefore, the FMO4 group exhibited a significant increase in plasma low-density lipoprotein cholesterol and triglyceride levels (p < 0.05). Compared to the control group, total superoxide dismutase and catalase activities were significantly increased in the FMO4 group (p < 0.05). The FMO2 and FMO4 groups exhibited an anti-inflammatory response by inhibiting the expression levels of toll-like receptor 4, nuclear factor-kappa B, and tumor protein P53 mRNA (p < 0.05). In conclusion, the 4.4% FMO treatment increased muscle crude protein content, enhanced lipogenesis, and improved the hepatic antioxidant abilities of M. amblycephala juveniles, while 2.2% FMO and 4.4% FMO improved the liver anti-inflammatory capacities.

Foliar Applications of Calcium, Silicon and Their Combination: A Tool to Improve Grape Composition and Quality

Foliar nutrient sprays are broadly used in commercial agriculture. To date, the application of Ca and Si has been little explored in vineyard production but may lead to positive responses at various levels. Therefore, the aim of this work was to evaluate the effect of supplying single or combined calcium (Ca, 120 mM) and silicon (Si, 120 mM) sprays in Tempranillo grape composition. Foliar treatment with Ca + Si foliar enhanced all families of aromatic compounds, whereas single Ca and Si sprays induced lower effects. Regarding phenolic compounds, all foliar treatments led to minor effects. However, all three foliar Ca and Si treatments increased the total grape amino acid content. Consequently, the application of combined Ca and Si sprays to a vineyard is recommended as a tool for improving grape quality.

Amino acid profile and protein quality of starter cultures fermented African Yam bean (Sphenostylis sternocarp) seed condiment

African yam bean seeds condiment is an unpopular nutritive local food seasoning compared to Iru and is mostly produced by natural fermentation. Production with a defined starter culture will give a novel functional condiment with enhanced nutritive values, especially amino acids, to prevent hidden hunger, shorten the fermentation time, and improve product uniformity. The effect of different monoculture bacterial starters and natural fermentation on the amino acids profile of condiments produced from African yam bean seeds was investigated. The result revealed a total of 18 amino acids with glutamic and aspartic acids as the most abundant amino acids in all the samples portions, with a range of values of 9.79-11.44 g/100 g protein and 9.20 -10.67 g/100 g protein respectively. The inoculated samples were rich in all the amino acids quality than un-inoculated. The total amino acid content of the samples was significantly different (p ≤ 0.05). Bacillus amyloliquefacien starter fermented sample had the highest total amino acid value of 95.80 g/100 g protein while Bacillus subtilis fermented and un-inoculated seed portion samples had a total amino acid value of 86.81 g/100g and 74.04 g/100 g protein respectively. The essential amino acids (EAA10) were significantly different (p ≤ 0.05) and were in the range of 35.75-46.32 g/100 g protein with leucine, arginine, lysine, valine, isoleucine and phenylalanine the most abundant in inoculated and un-inoculated samples portions and were more concentrated in inoculated samples. Non-essential amino acids were slightly higher (38.29 - 49.47 g/100 g protein) than the total essential amino acids. The total acidic amino acids varied from 18.99 – 22.11 g/100 g protein and were significantly higher than the basic amino acids (12.88 – 15.95 g/100 g protein). The amino acid content of the Bacillus amyloliquefacien starter fermented sample was better enhanced than the sample fermented with Bacillus subtilis starter. The study concluded that controlled fermented condiments produced with B. amyloliquefacien culture boosted the amino acids value and profile.

Evaluation of IgG/IgE-binding capacity and functional properties of enzymatic hydrolysis in skimmed cow milk system.

Cow's milk (CM) allergy is a common food allergy that seriously impacts the growth and development of infants and children. However, CM is an important source of nutrients, and few studies focus on the effects of enzymatic hydrolysis treatment on the whole skimmed CM system. In this study, the IgG/IgE-binding and functional properties of Alcalase-, Protamex-, and Flavourzyme-treated skimmed CM (AT, PT, and FT, respectively) were systematically evaluated. The results showed that the treatment groups were mainly composed of low molecular weight (MW) peptides (<3kDa), accounting for 94.85%-97.90%. Additionally, the IgG reactivity of these peptides was significantly lower (p<0.05) than those of higher MW peptides (10-30kDa and >30kDa). The IgE reactivity of FT with higher MW peptides was the lowest among these groups, with the OD value reaching 0.089. Moreover, the total amino acid content of hydrolysates of skimmed CM (HM) increased significantly (skimmed CM, 5.94µg/mL; AT, 123.70 µg/mL; PT: 136.20µg/mL; FT, 988.72µg/mL) compared to that in skimmed CM. A total of 10, 10, and 7 flavor compounds were increased in AT, PT, and FT, respectively. Furthermore, the solubility, foamability, and emulsifying ability of HM were significantly improved, being 2.17-fold, 1.52-fold, and 1.96-fold higher in PT than in skimmed CM. These results lay a theoretical foundation for the development of hypoallergenic dairy products.

Artificial spawning, hatchery and culture of the tropical sea cucumber (Holothuria leucospilota) using non-living food

Artificial breeding and farming of sea cucumber is considered as a sustainable way to meet market demand and minimize the pressure on wild populations. This study reports a method for large-scale artificial spawning, hatchery and culture of the tropical sea cucumber (Holothuria leucospilota). Spawning induction was performed by constant stimulation and dry shock. Both methods could obtain active and healthy fertilized eggs, but constant stimulation could get a greater oviposition amount of H. leucospilota. Among the six tested non-living food, the Spirulina platensis meal contains the highest contents of crude protein and total amino acids, and the Chlorella pyrenoidosa powder contains most abundant types of fatty acid. However, only the C. pyrenoidosa powder fed larvae could successfully develop to doliolaria stage. H. leucospilota fed C. pyrenoidosa powder had similar (P > 0.05) growth rate and survival rate but higher (P < 0.05) metamorphosis rate than that fed living Chaetoceros muelleri. The contents of crude protein and total amino acids of Saccharomyces cerevisiae yeast meal between that of C. muelleri and C. pyrenoidosa powder, but it failed to induce larval metamorphosis. The best diet scheme was mixing C. pyrenoidosa powder, S. cerevisiae yeast powder and sea mud followed by the ratio of 2:1:2 with the installment feeding mode, which reached the highest development rate of H. leucospilota. In summary, a simple and successful technology for large-scale artificial reproduction of H. leucospilota is set up in this study, which not only provide an excellent candidate for aquaculture in tropical regions, but also conducive to recover and reconstruct the wild population of sea cucumber.

Bunch microclimate influence amino acids and phenolic profiles of Pinot noir grape berries.

The increase of temperature due to climate change at different phenological stages of grapevine has already been demonstrated to affect accumulation of primary and secondary metabolites in grape berries. This has a significant implication for Pinot noir especially in New Zealand context as these compounds can have direct and indirect effects on wine quality. This study investigates how varying bunch microclimate through changes in temperature applied at veraison stage can affect: fresh weight, total soluble solids, the accumulation of anthocyanins, total phenolics and amino acids of the grape berries. This was studied over two growing seasons (2018/19 and 2019/20) with Pinot noir vines being grown at two different temperatures in controlled environment (CE) chambers. The vines were exposed to 800 µmol/m2/s irradiance with diurnal changes in day (22°C or 30°C) and night (15°C) temperatures. This experimental set up enabled us to determine the accumulation of these metabolite at harvest (both seasons) and throughout berry development (second season). The results showed that berry weight was not influenced by temperature increase. The total soluble solids (TSS) were significantly increased at 30°C, however, this was not at the expense of berry weight (i.e., water loss). Anthocyanin content was reduced at higher temperature in the first season but there was no change in phenolic content in response to temperature treatments in either season. The concentrations of total amino acids at harvest increased in response to the higher temperature in the second season only. In addition, in the time course analysis of the second season, the accumulation of amino acids was increased at mid-ripening and ripening stage with the increased temperature. Significant qualitative changes in amino acid composition specifically the α-ketoglutarate family (i.e., glutamine, arginine, and proline) were found between the two temperatures. This study is the first to provide detailed analysis and quantification of individual amino acids and phenolics in Pinot noir in response to changes in temperature applied at veraison which could aid to develop adaptation strategies for viticulture in the future.

Effects of Dietary Lysine Level on Growth Performance and Protein Metabolism in Juvenile Leopard Coral Grouper (Plectropomus leopardus).

An 8-week feeding trial was conducted to evaluate the effects of dietary lysine level on growth performance and protein metabolism of juvenile leopard coral grouper (Plectropomus leopardus) and thereby obtained the optimal dietary lysine requirement of P. leopardus. Six isoproteic and isolipidic experimental diets were formulated to contain 1.10%, 1.69%, 2.30%, 3.08%, 3.56%, and 4.36% lysine of diets, respectively. Each diet was assigned at random to triplicate groups of 25 juveniles (initial mean weight is 10.57 g) per tank in a flow-through mariculture system maintained at 27-30°C. Dietary inclusion of 2.30-3.08% lysine improved the weight gain rate (WGR) and specific growth rate and decreased the feed conversion ratio (FCR) of juveniles (P < 0.05). The intestinal digestive enzyme (trypsin, amylase, and lipase) activities were overall enhanced by dietary inclusion of 3.08-3.56% lysine (P < 0.05). The mammalian target of rapamycin (mTOR) signaling pathway was activated in fish fed diets with 1.69-2.30% lysine by upregulating the relative expression levels of hepatic TOR and S6K1 (p70 ribosomal protein S6 kinase 1) but downregulating the relative expression level of hepatic 4E-BP2 (eIF4E-binding protein 2). Conversely, the amino acid response signaling pathway was inhibited in fish fed diet with 2.30% lysine by downregulating the relative expression levels of hepatic GCN2 (general control nondepressible 2), ATF3 (activating transcription factor 3), ATF4a (activating transcription factor 4a), and ATF4b (activating transcription factor 4b). Additionally, dietary 1.69-3.08% lysine enhanced the plasma total protein level and hepatic lysine α-ketoglutarate reductase activity but depressed the blood urea nitrogen level and hepatic adenosine monophosphate deaminase activity (P < 0.05). Moreover, dietary 3.08% lysine increased the contents of whole-body crude protein and total amino acids, while 1.69%-4.36% lysine depressed the whole-body lipid content (P < 0.05). These results indicated that optimal dietary lysine increased the digestive enzyme activities, promoted protein synthesis but depressed protein degradation, and thereby improved the growth performance of P. leopardus. Based on the second-order polynomial model, the optimal lysine requirement of juvenile P. leopardus for WGR, FCR, and lysine deposition was 2.60%-2.97% of diets (4.91%-5.60% of dietary protein).

Nutritional Profiling and Cytotoxicity Assessment of Protein Rich Ingredients Used as Dietary Supplements

In recent years, the scientific community has made significant progress in understanding nutrition, leading consumers to shift their preferences away from animal-based protein products and towards natural, plant-based protein sources. This study aimed to determine the nutritional value, in vitro cytotoxicity and antioxidant activity for different sources of high protein content products (pea, yeast, almond, spirulina and Pleurotus spp.) with potential usage as raw materials for dietary supplements, especially since these products do not benefit from stricter regulation requirements regarding their actual health benefits. The characterization of raw materials consisted in evaluation of their nutritional profile (by addressing moisture content, crude protein content, extractable fat, ash, carbohydrates) and microbial contamination (TAMC, TYMC, Enterobacteriaceae and β-glucuronidase positive Escherichia coli), total content of free amino acids, soluble proteins, phenols and flavonoids, as well as antioxidant activity through chemical assays. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release to evaluate the potential cytotoxicity of selected raw materials. Results obtained indicate high percentages of proteins for the pea powder (77.96%) and Spirulina powder (64.79%), Pleurotus spp. flour had strong antioxidant activity, while the highest contamination values were registered for Pleurotus spp. powder (4.6 × 105 CFU/g or 5.66 log CFU/g). Cytotoxicity results demonstrate that tested ingredients have an impact on the metabolic activity of cells, affecting cellular integrity and provoking leakage of DNA at several concentrations. While plant-based protein supplementation may appear to be a promising solution to balance our busy lives, there are several advantages and disadvantages associated with them, including issues related to their absorption rate, bioavailability, cytotoxicity and actual nutritional benefits.

Selenium enhances ROS scavenging systems and sugar metabolism increasing growth of sugarcane plants

Selenium (Se) beneficial effect on plants is related to an increase in nitrogen (N) assimilation and its role as an abiotic stress mitigator by reactive oxygen species (ROS) scavenging enhanced by antioxidant metabolism. This study aimed to evaluate sugarcane (Saccharum spp.) growth, photosynthetic and antioxidant responses, and sugar accumulation in response to Se supply. The experimental design was a factorial scheme 2 × 4: two sugarcane varieties (RB96 6928 and RB86 7515) and four Se application rates (0; 5; 10 and 20 μmol L−1) applied as sodium selenate in the nutrient solution. Leaf Se concentration increased under Se application in both varieties. The enzymes SOD (EC 1.15.1.1) and APX (EC 1.11.1.11) showed increase activities under Se application on variety RB96 6928. Nitrate reductase activity increased in both varieties resulting in the conversion of nitrate into higher total amino acids concentration indicating an enhanced N assimilation. This led to an increased concentration of chlorophylls and carotenoids, increased CO2 assimilation rate, stomatal conductance, and internal CO2 concentration. Selenium provided higher starch accumulation and sugar profiles in leaves boosting plant growth. This study shows valuable information regarding the role of Se on growth, photosynthetic process, and sugar accumulation in sugarcane leaves, which could be used for further field experiments. The application rate of 10 μmol Se L−1 was the most adequate for both varieties studied considering the sugar concentration and plant growth.

Effects of methionine treatment on storage quality and antioxidant activity of postharvest jujube fruit

Jujube fruits usually suffer from physiological disorders or infectious diseases during storage, leading to quality deterioration, softening, or rotting. Therefore, this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality. Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid. Methionine treatment effectively delayed the decrease of firmness, soluble solids, ascorbic acid, and lignin contents in jujube fruit. Methionine treatment reduced the content of alanine and phenylalanine, and increased the content of glycine in jujube fruit, but displayed no significant effect on total amino acid content. In addition, jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity, both in free and bound forms. Compared with the control, methionine treatment also significantly increased the content of individual phenolic acid fractions (gallic acid, vanillic acid, and syringic acid) and flavonoid fractions (catechin, epicatechin, rutin) in free form as well as individual phenolic acid fractions in bound form (gallic acid and ferulic acid) in jujube fruits. Overall, this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.

Structural, physicochemical, and immune-enhancing properties of edible insect protein isolates from Protaetia brevitarsis larvae.

Edible insects are promising future food resources globally. Herein, the structural, physicochemical, and bio-functional properties of edible insect protein isolates (EPIs) extracted from Protaetia brevitarsis larvae were investigated. The results showed that EPIs have a high total essential amino acid content; moreover, β-sheet is the major secondary protein structure. The EPI protein solution was highly soluble and electrically stable and did not aggregate easily. In addition, EPIs exhibited immune-enhancing properties; EPI treatment of macrophages induced the activation of macrophages and consequently promoted the production of pro-inflammatory mediators (NO, TNF-α, and IL-1β). Moreover, macrophage activation of EPIs was confirmed to occur through the MAPK and NF-κB pathways. In conclusion, our results suggest that the isolated P. brevitarsis protein can be fully utilized as a functional food material and alternative protein source in the future food industry.

Evaluation of probiotic potentiality of GM-Lac (Lactobacillus and Bifidobacterium) in juvenile Asian seabass Lates calcarifer

This study was conducted to evaluate the probiotic potentiality of GM-Lac (a mixture that comprises four lactic acid bacteria (LAB) strains– Limosilactobacillus fermentum GMNL-93, Lactiplantibacillus plantarum GMNL-141, Lacticaseibacillus casei GMNL-277, and Bifidobacterium lactis GMNL-550) applied in fish aquaculture. First, the four LAB isolates (GMNL-93, −141, −277, and −550) constituting GM-Lac were tested individually for antimicrobial activity in vitro. Then, GM-Lac was incorporated in fish feed at a dose of 5 × 106 cfu (g feed)−1 and fed to Asian seabass (Lates calcarifer) juveniles for eight weeks to assess the effects on growth performance, gastrointestinal (GI) histology and microflora, muscle amino acid composition, and disease resistance. According to the result of the zone of inhibition test, each GMNL strain presented noticeable antimicrobial activity against bacterial pathogens common in aquaculture. After the 8-week feeding trial, the fish in the GM-Lac group had higher final weight (p < 0.05), percent weight gain, specific growth rate, and feed intake than the fish in the Ctrl group, along with higher microvillus length in GI tract (p < 0.05) and greater total amino acid concentration in muscle. Furthermore, the relative abundance of microbial phyla in the GI tract of the fish fed with GM-Lac changed significantly, accompanied by increasing probiotic bacteria and decreasing pathogenic bacteria in the intestine and pyloric caeca. In the challenge test, the fish receiving GM-Lac all survived without any clinical symptoms when challenged with Streptococcus iniae. This study concludes that GM-Lac (the combination of L. fermentum GMNL-93, L. plantarum GMNL-141, L. casei GMNL-277, and B. lactis GMNL-550) is recommended as a probiotic supplement with high potential in aquaculture practice, which has antimicrobial activities against aquatic pathogens and benefits in enhancing growth performance, intestinal health, muscle amino acid composition, and disease resistance in juvenile Asian seabass.

Low rumen degradable starch promotes the growth performance of goats by increasing protein synthesis in skeletal muscle via the AMPK-mTOR pathway.

Since starch digestion in the small intestine provides more energy than digestion in the rumen of ruminants, reducing dietary rumen degradable starch (RDS) content is beneficial for improving energy utilization of starch in ruminants. The present study tested whether the reduction of rumen degradable starch by restricting dietary corn processing for growing goats could improve growth performance, and further investigated the possible underlying mechanism. In this study, twenty-four 12-wk-old goats were selected and randomly allocated to receive either a high RDS diet (HRDS, crushed corn-based concentrate, the mean of particle sizes of corn grain=1.64mm, n=12) or a low RDS diet (LRDS, non-processed corn-based concentrate, the mean of particle sizes of corn grain >8mm, n=12). Growth performance, carcass traits, plasma biochemical indices, gene expression of glucose and amino acid transporters, and protein expression of the AMPK-mTOR pathway were measured. Compared to the HRDS, LRDS tended to increase the average daily gain (ADG, P=0.054) and decreased the feed-to-gain ratio (F/G, P<0.05). Furthermore, LRDS increased the net lean tissue rate (P<0.01), protein content (P<0.05) and total free amino acids (P<0.05) in the biceps femoris (BF) muscle of goats. LRDS increased the glucose concentration (P<0.01), but reduced total amino acid concentration (P<0.05) and tended to reduce blood urea nitrogen (BUN) concentration (P=0.062) in plasma of goats. The mRNA expression of insulin receptors (INSR), glucose transporter 4 (GLUT4), L-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (4F2hc) in BF muscle, and sodium-glucose cotransporters 1 (SGLT1) and glucose transporter 2 (GLUT2) in the small intestine were significantly increased (P<0.05) in LRDS goats. LRDS also led to marked activation of p70-S6 kinase (S6K) (P<0.05), but lower activation of AMP-activated protein kinase (AMPK) (P<0.05) and eukaryotic initiation factor 2α (P<0.01). Our findings suggested that reducing the content of dietary RDS enhanced postruminal starch digestion and increased plasma glucose, thereby improving amino acid utilization and promoting protein synthesis in the skeletal muscle of goats via the AMPK-mTOR pathway. These changes may contribute to improvement in growth performance and carcass traits in LRDS goats.

Total amino acid level affects the results of standardized ileal digestibility assays for feed ingredients for swine.

It has been demonstrated that the fiber content of oilseed meals and total amino acids (AA) in distillers' grains products affects standardized ileal digestibility (SID) values from swine assays and that total protein concentration affects the AA digestibility in assays using chickens. This analysis was conducted to test the hypothesis that the total AA content of test samples affects the SID assay results. Databases containing total AA profiles and SID values of 20 feedstuffs commonly fed to pigs from 2 sources, AMINODat 5.0 (Evonik Industries, 2015) and the Nutrient Requirements of Swine, 12th edition (NRC, 2012) were used to compare AA concentration effects on standardized ileal digestibility coefficients. Databases were compared with AA and SID available in both data sets. The total AA values were similar for the 2 databases with an R 2 of 0.979 (P<0.001). The linear relationship between digestibility coefficients from the 2 databases was highly significant, an R 2 of 0.810 (P<0.001). Both databases had increased SID values with increasing AA contents within and across feed ingredients. The SID=f(AA concentration) relationship was confirmed with an individual paper. Since SID, as typically measured, is a function of both digestion and absorption, both processes following Michaelis-Menten kinetics, SID=f(AA concentration) may simply be a natural phenomenon. Other reasons for the relationship were explored. Methods of estimating endogenous AA losses and misapplication statistical procedures may contribute to variation in results and at least partially explain why SID=f(AA concentration).

Comparative Study on Nutritional Characteristics and Volatile Flavor Substances of Yak Milk in Different Regions of Gannan.

This study aimed to investigate the nutritional properties of yak milk in various areas of Gannan. The milk composition analyzer, automatic amino acid analyzer, and flavor analyzer were used to detect the conventional nutrients, amino acids, and volatile flavor substances of 249 yak milks in Meiren grassland, Xiahe grassland, and Maqu grassland (hereinafter referred to as Meiren yak, Xiahe yak, and Maqu yak) in the Gannan area. The results showed that the fat content of Meiren yak milk was significantly higher than that of Maqu yak and Xiahe yak (p < 0.05). The protein content of Meiren yak milk was significantly higher than that of Xiahe yak (p < 0.05), but not significantly different from that of Maqu yak (p > 0.05). The casein content in the milk of Maqu yak was significantly higher than that of Meiren yak and Xiahe yak (p < 0.05). There was no significant difference in the lactose content of yak milk in the three regions (p > 0.05). The content of glutamic acid in the milk of Meiren yak, Xiahe yak, and Maqu yak was noticeably high, which was 1.03 g/100 g, 1.07 g/100 g, and 1.10 g/100 g, respectively. The total amino acid (TAA) content was 4.78 g/100 g, 4.87 g/100 g, and 5.0 g/100 g, respectively. The ratios of essential amino acids (EAA) and total amino acids (TAA) in the milk of Meiren yak, Xiahe yak, and Maqu yak were 42.26%, 41.27%, and 41.39%, respectively, and the ratios of essential amino acids (EAA) and nonessential amino acids (NEAA) were 73.19%, 70.28%, and 70.61%, respectively. In the yak milk samples collected from three different regions, a total of 34 volatile flavor compounds were detected, including 10 aldehydes, five esters, six ketones, four alcohols, two acids, and seven others. The main flavor substances qualitatively obtained from Meiren yak milk were ethyl acetate, n-valeraldehyde, acetic acid, heptanal, and n-hexanal. Xiahe yak milk mainly contains ethyl acetate, isoamyl alcohol, n-valeraldehyde, heptanal, and ethyl butyrate. Maqu yak milk mainly contains ethyl acetate, n-valeraldehyde, isoamyl alcohol, heptanal, ethyl butyrate, and n-hexanal. Principal component analysis showed that the flavor difference between Xiahe yak and Maqu yak was small, while the flavor difference between Xiahe yak, Maqu yak, and Meiren yak was large. The findings of this research can serve as a foundation for the future advancement and application of yak milk.

Assessing the Changes in Protein Content During the Ensilage of the Indian Mackerel (Rastrelliger kanagurta) by Biological Method

Fish silage is a liquefied product resulting from tissue hydrolysis and the richness of the silage is characterized by its nutritional profile comprising of proteins, amino acids, and fats. For the production of fish silage of high nutritional value, a precise assessment of the degree of hydrolysis, particularly proteolysis becomes a paramount importance. The goal of this study is to assess the changes in protein content in fish silage prepared from the Indian mackerel (Rastrelliger kanagurta) waste using 10% (v/w) sugarcane molasses, during 8 days of fermentation (DoF). The resultant ensiled product was evaluated for changes in titratable acidity, nutrients, total protein, total carbohydrate, total lipids content, and amino acid composition. Altogether, 17 types of amino acids were identified. Concentrations of total amino acids (TAAs, 15.627 ± 0.03 mg/g) and free amino acids (5.556 ± 0.08 mg/g) peaked at the end of 6 DoF with the predominance of histidine, arginine, alanine, asparagine, aspartic acid, and glutamic acid. Results of the non-metric multidimensional scaling (nMDS) plots and one-way analysis of similarities (ANOSIM) test indicated significant differences in the composition of TAAs at different DoF were discernible (nMDS, stress 0.03162, one-way ANOSIM R = 1; p < 0.0001). Similarity percentage (SIMPER) analysis indicated that the maximum content of amino acids (TAA and FAA) were released in silage during 4–6 DoF. A significant difference was observed in concentrations of most amino acids except cysteine, serine, and tryptophan (ANOVA, p < 0.05) at 2, 4, 6 and 8 DoF. Considering the vital role played by amino acids in providing resistance to plant pathogens as well as contributing to animal nutritional supplements, the results of the present study are highly noteworthy.

Utilization of fish protein isolates to supplement oat-based cookies and assessment of end product quality.

Bullseye and Pacu fish processing waste were valorized through its conversion into functional protein isolates, followed by the utilization of recovered proteins to supplement oat-based cookies at different levels (0, 2, 4, 6, 8 and 10g/100g) and baking temperatures (100, 150, 170, 180, 190 ˚C). With different replacement ratios and baking temperatures, the best selection was made at (4 and 6%) and baking temperatures (160 and 170 ˚C) for BPI (Bullseye protein isolate) and PPI (Pacu protein isolate) based cookies, respectively based on sensory and textural characteristics. The developed products were analyzed for its nutritional, physical, textural, and sensory quality. No significant differences were found in the moisture and ash contents of the cookies from different lots, while the protein content was highest for cookies with 6% PPI. The spread ratio was lower reported for the control cookies compared to the fish protein isolate-based counterpart (p < 0.05), and it decreased with increasing thickness of cookies. Significantly higher total essential amino acid values were obtained in cookies supplemented with 6% Pacu protein isolates, whereas 4% Bullseye protein isolate-supplemented cookies were higher in total non-essential amino acid content. The total plate count was higher in control cookies (0.35 ± 0.33cfu/g) compared to fish protein isolate-supplemented cookies. The hardness values were maximum for control group cookies (19.14 ± 0.98 N) compared to protein isolate incorporated cookies (17.22 ± 1.05 N and 16.26 ± 0.9 N). However, the difference among the all-treatment group is not significant (p > 0.05).

Physical and nutritional properties of Chinese Steamed Bun (mantou) made with fermented soy milk

The incorporation of fermented soy milk as an ingredient in Chinese steamed bun (CSB) was investigated to improve nutritional properties and flavour. Soy milk, fermented with lactic acid bacteria (LAB) isolated from sourdough, was used at a level of 40% to prepare CSB. According to the rheological and microstructural analyses, the addition of fermented soy milk effectively improved the internal structure of the dough. CSB containing fermented soy milk had better texture properties. The protein content of CSB increased from 7.17% to 8.83%, and the fat content increased from 0.75% to 1.22%. The total phenolic compounds (TPCs) increased by 35.79%, the total flavonoids compounds (TFCs) increased by 100.08%, and the scavenging rate against DPPH increased by 8.01%. The antinutritional compounds (e.g., condensed tannins, phytic acid, total saponins) were significantly reduced by 43.35%, 21.28% and 52.18%, respectively. The in vitro protein digestibility (IVPD) increased by 10.69%, and the total free amino acids (TFAAs) concentration increased from 65.16 mg/g to 73.25 mg/g. In addition, the glucose content of CSB decreased by 13.61%, and fermented soy milk significantly increased the flavour compounds. The results confirmed that fermented soy milk could be a promising supplement for potential industrial applications.

Comparative performances of different farming systems and associated influence of ecological factors on Gracilaria sp. seaweed at the south-east coast of the Bay of Bengal, Bangladesh

The production performance and biochemical composition of agar-enriched Gracilaria sp. were evaluated under three farming systems (off-bottom net, floating long-line and off-bottom long-line) from October 2021 to April 2022. For this study, 25 off-bottom long-line (14 m × 5 m), 20 off-bottom net (1.8 m × 3.5 m), and 10 floating long-line (10 m × 3 m) were established and managed in a participatory farming approach with coastal communities at the south-east coast of the Bay of Bengal, Bangladesh. While growing to a length of 30–40 cm, Gracilaria sp. was partially harvested every 15–30 days, depending on the culture months. The average biomass production in the floating long-line system was 135% and 67.2% higher than the off-bottom long line and off-bottom net culture systems, respectively. Harvested Gracilaria sp. from floating culture was very clean, mostly free from encrusting organisms and impurities, and had an attractive reddish coloration. Multivariate analysis demonstrated that the growth performances of Gracilaria sp. were positively influenced by high salinity, dissolved oxygen, and nutrient concentration and negatively influenced by high temperature, turbidity, and total suspended solids. Gracilaria sp. harvested from the floating long-line system had higher amount of protein and lipids compared to the off-bottom systems. The total essential amino acid content of Gracilaria sp. in the floating long-line system was 18.4% and 13.3% higher (p < 0.05) than in off-bottom long-line and off-bottom net culture systems, respectively. Among the 10 minerals analyzed, Ca, K, and Zn contents were significantly higher (p < 0.05) in the floating long-line system. Among fatty acids, the n6-PUFA content of Gracilaria sp. in the floating long-line system was 11.2% higher (p < 0.05) than in the off-bottom long-line system. The Gracilaria sp. from the floating long-line culture system contained 18.8–21.3% higher agar than the off-bottom systems. The study also revealed that Gracilaria sp. obtained from the floating long-line system contained significantly lower heavy metals (Cr, Cd, Pb, and As) than the off-bottom systems. The findings of the present study demonstrated that raft-based floating long-line systems could be a promising culture technology for the production of agar-enriched Gracilaria sp. along the coastal areas of Bangladesh and elsewhere.

Changes in flavors profiles of stewed bone-in lamb loin during cooking by DHS/GC-MS combined with electronic bionic systems

To identify the changes in flavor profiles of bone-in lamb loin during cooking, the volatile flavor compounds, free amino acid, and 5ʹ-nucleotide concentration were evaluated by using dynamic headspace sampling-gas chromatography-mass spectrometry, electronic bionic system, sensory evaluation. The results showed the total concentration of volatile flavor compounds significantly increased with prolonged cooking time. Nonanal, hexanal, heptanal, 1-octen-3-ol, eugenol, eucalyptol, and 3,7-dimethyl-1,6-octadien-3-ol were the key odor compounds. The total free amino acid (TFAA) concentration significantly decreased after heat treatment, but the proportion of umami free amino acids significantly increased with cooking time (P < 0.05). The equivalent umami concentration (EUC) first increased then decreased in 100 °C group (peak at 1.5 h), compared with the continuous increase in 75 °C group. Meanwhile, an analysis of bionic system showed the samples had significant differences in bitterness, astringency, umami, saltiness, and richness. The 5ʹ-nucleotide, and EUC positively correlated with umami and sensory valuation indicators. Bone-in lamb loin heated at 100 °C exhibited higher concentrations of alcohols, aldehydes, esters, heterocycles, and higher taste of bitterness and saltiness, while the 75 °C groups exhibited higher taste of umami at longer heat times. This study provides a theoretical basis for flavor control of bone-in lamb.