Automatic Amino Acid Analyzer Research Articles

Analysis of free amino acids and evaluation of the quality of gallnut honeys from different geographical areas

AbstractGallnut honey, a typical Chinese medicinal commodity, is produced from the nectar of Rhus chinensis Mill. Gallnut honey is very popular with consumers because of its health effects and nutritional value, but its specific nutritional composition and medicinal components are not clear. Free amino acids are important nutritional components of honey, and can provide relevant information about the honey, such as geographical and botanical origin, as well as adulterations. The aim of this paper was to explore the free amino acid characteristics of gallnut honeys in different areas. 18 free amino acids from 17 places in China were determined by automatic amino acid analyser analysis, and the geographical characteristics were studied by principal component analysis and cluster analysis. Results showed that gallnut honey is rich in free amino acids. A total of 12 types of free amino acids were detected in all honey-producing areas, and the total amino acid content was 0.132–0.292 g/100 g. Due to its free amino acid content gallnut honey has high nutritional supplement potential, and exhibits good pharmacodynamic activity and special taste characteristics. Flavour-related free amino acids were primarily aromatic free amino acids and umami free amino acids. Pharmacodynamic free amino acids accounted for 61.22–83.85%. Results also showed that free amino acids contribute to the geographical tracing of honey, and samples of gallnut honey at different altitudes can be distinguished by cluster analysis.

Metagenomic and Metabolomic Profiling Reveals the Differences of Flavor Quality between Hongqu Rice Wines Fermented with Gutian Qu and Wuyi Qu.

Jiuqu (starter) makes an important contribution to the formation of the flavor characteristics of Hongqu rice wine (HQW). Gutian Qu (GTQ) and Wuyi Qu (WYQ) are two kinds of Jiuqu commonly used in HQW brewing, but the comparison of the two kinds of HQW is still insufficient at present. The objective of this study was to compare the dynamic changes of amino acids (AAs), higher alcohols (HAs), bioamines (BAs), volatile flavor compounds (VFCs), and microbial communities in HQW fermentation, with GTQ and WYQ as starter. This study used an automatic amino acid analyzer, GC, HPLC, and GC-MS to detect AAs, HAs, Bas, and VFCs during fermentation; metagenomic sequencing technology was used to elucidate the microbial community and its functional characteristics. The results showed that the contents of AAs and HAs in HQW brewed with WYQ (WYW) were significantly higher than those in HQW brewed with GTQ (GTW). On the contrary, the majority of BAs in GTW were significantly higher than those in WYW. The composition of VFCs in WYW and GTW were obviously different, as most of the VFCs were notably enriched in WYW, while ethyl caproate, isoamyl acetate, ethyl heptanoate, ethyl nonanoate, 1-decanol, citronellol, phenethyl acetate, and hexanoic acid were more abundant in GTW. Burkholderia gladioli, Pantoea dispersa, Weissella cibaria, Monascus purpureus, and Saccharomyces cerevisiae were the predominant microbial populations in GTW brewing at the species level, while Sphingomonas sp., Kosakonia cowanii, Enterobacter asburiae, Leuconostoc lactis, Aspergillus niger, and Saccharomyces cerevisiae were the dominant microbial species in WYW brewing. The abundance of functional genes involved in BAs biosynthesis were much higher in GTW brewing, while the abundance of functional genes related to the metabolism of characteristic VFCs were much higher in WYW brewing. Collectively, these findings provided evidence for elucidating the effects of Jiuqu and microbial communities on HQW flavor quality, and laid a solid foundation for the improvement of HQW flavor quality.

Preparation of umami peptides from chicken breast by ultrasound-assisted gradient dilution feeding substrate and study of their formation mechanism

Gradient dilution feeding substrate (GDFS) is regarded as an effective method for the production of active peptides, as it compensates for substrate limitations and minimizes substrate contamination of the ultrafiltration membrane. This study further investigated the impact of ultrasound-assisted gradient dilution feeding substrate (UA-GDFS) on the peptide yield and the intensity of umami. The chicken breast was used as ingredients. The umami compounds in the hydrolysate were determined using an automatic amino acid analyzer and HPLC. The hydrolysate's umami intensity was determined by electronic tongue in all modes. These findings indicated that UA-GDFS enhanced the umami intensity and peptide yield. Hydrolysate from UA-GDFS with molecular weight below 1 kDa was analyzed by nano-scale liquid chromatography-tandem mass spectrometry (Nano-HPLC-MS/MS). Electronic tongue analysis showed that GPSGPVG and VDGPSGK had umami taste and could enhance the umami taste of monosodium glutamate (MSG) solution. Asn68 and His145 were important sites on T1R3 for umami peptide binding.

Effects of different thermal processing methods on amino acid, fatty acid, and volatile flavor substance contents of Aohan millet (Golden seedling millet)

AbstractAohan millet has been cultivated for 8000 years and has rich nutritional value, such as high‐quality fatty acids and amino acids. Thermal processing is a conventional approach to food preparation. However, the effect of thermal processing on the formation of flavor substances in millet has not been clarified. Therefore, in this study, the effects of three different thermal processing techniques, namely, steaming, stir‐frying, and puffing, on the amino acids, fatty acids, and volatile flavor substances of Aohan millet were investigated using high‐speed automatic amino acid analyzer, headspace solid‐phase microextraction method, combined with gas chromatography–mass spectrometry (HS‐SPME/GC–MS) and gas chromatography (GC) with Aohan millet from Inner Mongolia as the raw material. All three thermal processing methods notably reduced the levels of protein, starch, polyphenols, and flavonoids in Aohan millet when compared to the raw millet (p < .05). Amino acid and fatty acid contents demonstrated an increase in fried and puffed millet relative to steamed millet, with notable distinctions in amino acid and fatty acid contents between these two groups. Following the steaming process, there was a significant increase in the flavor compounds of Aohan millet, rising from 53 to 80, while this increase was not observed in the other two groups. The correlation analysis suggested that the formation of flavor compounds was predominantly influenced by the types and levels of amino acids. The study suggested that different heat treatments affected the amino acid, fatty acid, and more significantly flavor material content and composition of Aohan millet. In conclusion, steaming treatment could retain more nutrients and richer flavor substances; while puffing treatment would enhance amino acid and fatty acid content, which provides a fundamental basis for scientifically guided processing and rational culinary application of Aohan millet.

Comparison of different derivatisation for amino acids determination of foie gras by high performance liquid chromatography (HPLC)

ABSTRACT 1. In order to compare the difference between different derivatisations for amino acids determination of foie gras via, reversed phase high performance liquid chromatography (HPLC), O-phthalaldehyde and 9-fluorenyl-methyl chloroformate (OPA-FMOC group), phenylisothiocyanate (PITC group) and 6-Aminoquinolyl-N-hydrox-ysuccinimidyl Carbamate (AQC group) were applied to derivatisation reagent in this current experiment. The determination results of automatic amino acid analyser were applied, and 17 amino acids were detected by these three derivatisation methods. 2. The running times of OPA-FMOC group, PITC group and AQC group were 18, 45 and 35 min, respectively. There was a large difference between the results of OPA-FMOC group and results from the automatic amino acid analyser, although the difference between the results from PITC and the automatic amino acid analyser was minimal. 3. In conclusion, the running time of OPA-FMOC group was shorter than that of PITC group and AQC group; the accuracy of the former was better than the OPA-FMOC group and AQC group for the determination of amino acid of foie gras.

Effects of the photovoltaic fishery culture model on muscle nutritional quality and volatile flavor compounds of Litopenaeus vannamei

This study used Litopenaeus vannamei to compare the muscle nutritional quality and volatile flavor compounds of animals raised in the photovoltaic fishery culture model (PM) and the common pond breeding model (CM). Amino acids, fatty acids, and volatile flavor substances were identified and analyzed using an automatic amino acid analyzer and headspace solid phase microextraction(HS-SPME) combined with GC/MS. There were no significant differences between the two culture models in terms of general nutrients, mineral contents, and amino acid compositions in the muscles of L. vannamei. In the PM group, the proportion of flavor amino acids in total amino acids was higher. Based on the amino acid score (AAS) and chemical score (CS), it was found that methionine and cystine were the first limiting amino acids in the muscle samples. The essential amino acid index (EAAI) value was approximately 77 for both models, indicating high-quality proteins. The muscles contained nine types of fatty acids, with the PM group showing significantly higher levels of both monounsaturated and total fatty acids. A total of 23 volatile flavor compounds were identified in both models. The contents of 1-nonanal, n-tridecane, and alpha-terpineol were higher when cultured in the PM. Conversely, the contents of hexanal, 2-ethylhexanol, and dipentene were lower in the PM group. The photovoltaic fishery culture model has the potential to enhance income through photovoltaic power generation. In addition, this study found that the fatty acid composition of L. vannamei was improved in the PM, without compromising muscle composition or flavor. These results provide a theoretical basis for evaluating the meat quality of L. vannamei under different culture models and offer data to support and guide the promotion of the PM.

An Optimized Microwave-Assisted Digestion Method to Analyze the Amino Acids Profile of Quisqualis Fructus from Different Planted Origins.

This study aims to establish a rapid and convenient microwave-assisted digestion method for sample pretreatment to determine amino acid profiles in natural products. This method was applied to analyze the amino acid profiles of Quisqualis Fructus (QF) from different planted origins. The microwave-assisted digestion conditions were optimized by a response surface methodology (RSM), and 17 amino acids in different planted origins of QF were determined by an automatic amino acid analyzer according to the optimized digestion conditions. The contents of 17 amino acids in QF from different planted origins were further analyzed by fingerprint and chemometric analysis. The temperature of microwave digestion at 167 °C, time of microwave digestion at 24 min, and a solid-liquid ratio of 46.5 g/mL was selected as the optimal digestion conditions. The total content of 17 amino acids in QF from different planted origins ranged from 71.88 to 91.03 mg/g. Amino acid composition and nutritional evaluation indicated that the content of medicinal amino acids was higher than aromatic amino acids. The results of fingerprint analysis reflected that the similarity between the 16 batches of QF ranged from 0.889 to 0.999, while chemometrics analysis indicated amino acid content in QF varied from different planted origins, and six important differential amino acids were screened. Compared with the traditional extraction method, microwave-assisted digestion with response surface optimized has the advantages of rapidity, convenience, and reliability, which could be used to study the amino acid profiles in natural products. The amino acid profile of QF indicated that it has a rich medicinal nutritional value. Different planted origins of QF have a high degree of similarity and could be effectively distinguished by chemometric analysis.

Understanding the correlation between formation of flavor compounds and dominant bacteria during Luoyang mung bean sour fermentation

To understand the change of the overall flavor component, including volatile compounds and free amino acid, Luoyang mung bean sour (LMBS) was investigated by gas chromatography-mass spectrometry (GC-MS) and automatic amino acid analyzer. The results showed that the beany flavor compounds, including hexanal, 2-hexenal, hexanol, and 1-octene-3-ol, significantly decreased or even disappeared. The concentration of esters and acids, represented by caproic acid and hexyl acetate, increased during LMBS fermentation. By detecting the free amino acids, it was found that the umami taste of glutamic acid (Glu) and aspartic acid (Asp) were the dominant amino acids. Among the 7 metabolites tested, lactic acid exhibited the highest concentration and continued to accumulate during fermentation. Leuconostoc, Enterobacter, Lactobacillus, Citrobacter Pediococcus, and Lactococcus were identified as the dominant bacterial groups that exhibited fluctuations during LMBS fermentation. Ultimately, Lactobacillus emerged as the dominant species. The network of Spearman correlation analysis was employed to uncover the relationship between bacterial community and flavor compounds during the fermentation of LMBS. For the dominant bacteria, Leuconostoc, Pediococcus, and Lactobacillus were positively correlated with acetic acid, lactic acid, citric acid, alcohol, sweet and umami amino acids, while negatively correlated with ketones alcohols and bitter amino acids.

Effect of Different Cooking Methods on the Aroma and Taste of Chicken Broth.

A single combi oven, known for its versatility, is an excellent choice for a variety of chicken soup preparations. However, the impact of universal steam ovens on the flavor quality of chicken soup remains unclear. This study aimed to explore the impact of different cooking methods on the aroma and taste of chicken soup. Three cooking methods with various stewing times were compared: ceramic pot (CP), electric pressure cooker (EPC), and combi oven (CO). Analyses were conducted using electron-nose, electron-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), automatic amino acid analysis, and chemometric methods. A total of 14 amino acids, including significant umami contributors, were identified. The taste components of CP and CO chicken soups were relatively similar. In total, 39 volatile aroma compounds, predominantly aldehydes, ketones, and alcohols, were identified. Aldehydes were the most abundant compounds, and 23 key aroma compounds were identified. Pearson's correlation analyses revealed distinct correlations between various amino acids (e.g., glutamic acid and serine) and specific volatile compounds. The aroma compounds from the CP and CO samples showed similarities. The results of this study provide a reference for the application of one-touch cooking of chicken soup in versatile steam ovens.

РАЗРАБОТКА ТЕХНОЛОГИИ ПИЩЕВОЙ ДОБАВКИ ИЗ МОДИФИЦИРОВАННОЙ ФАСОЛИ ДЛЯ ИСПОЛЬЗОВАНИЯ В РЕЦЕПТУРАХ МЯСНЫХ ГЕРОДИЕТИЧЕСКИХ ПРОДУКТОВ

The objective of the study is to develop a technology for producing a food additive from sprouted beans of the Pobeditel variety grown in the Republic of North Ossetia – Alania in order to add it to the recipes for functional meat products of gerodietetic orientation. Objectives: theoretical substantiation of the possibilities of using a food additive from regional plant resources in the production of functional meat products of gerodietetic orientation; development of a technology for producing a food additive - bean protein concentrate (BPC) from modified beans of the Pobeditel variety grown in the Republic of North Ossetia – Alania; study of the chemical composition of the developed BPC; study of the functional and technological properties of the developed BPC; development of a recipe and technology for producing meat cutlets of gerodietetic orientation with the addition of the prebiotic BPC based on optimization of essential nutrients in the composition of raw ingredients using mathematical modeling; study of the physicochemical and organoleptic indicators, nutritional value of the finished meat product with the addition of the prebiotic BPC. The objects of the study are native beans, a food additive – prebiotic (BPC), a semi-finished meat product based on the food additive (BPC), and ready-made cutlets with the addition of BAP. Classical methods were used to study the chemical composition of the food additive – bean protein concentrate (BPC). The protein content was determined by the Kjeldahl method, the amino acid composition – by ion-exchange chromatography on an automatic amino acid analyzer from Hitachi. The amount of tryptophan was determined after alkaline hydrolysis. The functional and technological properties of the developed food additive – prebiotic were studied using the pressing method developed by R. Grau and R. Hamm, as modified by V. Volovinskaya and B. Kelman. The study assessed the composition and properties of the developed prebiotic. The principles of computer modeling of the recipe for a semi-finished meat product with BPC have been developed, corresponding to medical and biological requirements and providing the necessary adjustment for essential nutrients. The issues and methods of creating food products that have a functional purpose and are focused on gerodietetic nutrition in modern socio-economic, environmental and demographic conditions have been considered.

Characterization of Amino Acid Composition, Nutritional Value, and Taste of Fruits from Different Actinidia arguta Resources

The nutritional value and flavor and texture characteristics of fruits from different Actinidia argute resources were scientifically evaluated and compared. Using 35 A. arguta fruits as materials, the amino acid composition and content were determined by an automatic amino acid analyzer, and differentiation analysis, amino acid nutritional value evaluation, TAV flavor analysis, correlation analysis, PCA comprehensive evaluation, and cluster analysis were conducted to clarify the diversity of A. arguta resources in terms of amino acid content, composition, and flavor characteristics. Analysis of differential results showed that the A. arguta resource fruits contained 17 amino acids with a total amino acid content of 384.20∼2590.56 mg/100 g. The results of the nutritional value evaluation showed that the Leu of the fruits of the A. arguta resources all conformed to the ideal model proposed by FAO/WHO, and the Leu content of all the resources exceeded the human body’s needs, and it was also found that the first limiting amino acid of the Actinidia argute resources was Ile and the second limiting amino acid was Lys. TAV of the flavor-presenting amino acids was calculated to evaluate the flavor-presenting taste characteristics, and the amino acids that influenced the flavor of A. arguta fruit were Glu and Cys. PCA showed that the 2 principal components could better reflect the comprehensive information of amino acids in A. arguta, and the cumulative variance contribution rate was 87.88%, which could represent the main trend of amino acids in A. arguta. A comprehensive amino acid evaluation model was established, and the composite scores indicated that the top 5 excellent resources were S4, S10, S18, S25, and S30. Hierarchical cluster analysis classified the 35 A. arguta resources into 4 categories, which better reflected the differences in amino acid content and composition, nutritional value, and taste characteristics among A. arguta fruits from different collection sites.

Different characteristics of 40 kinds of free amino acids and 5-amino levulinic acid between wines and sakes (Japanese rice wines)

Based on a systemic analysis for the global burden of disease study from 1990 to 2016, the Global Burden of Diseases (GBD) 2016 Alcohol Collaborators reported that alcohol use was a leading risk factor for global disease burden and caused substantial health loss. However, alcoholic drink (wines and sakes) contains abundant nutrients, particularly fermentable amino acids derived from grapes and rice. Amino acid nutrition and metabolism is strongly associated with health and prevention against various diseases. The purpose of this study was to elucidate 40 kinds of free amino acid (FAA) profiles in wines and sakes. In addition, the present study also provided the contents of 5-aminolevulinic acid (5-ALA) involved in the vital functionality of mitochondria. FAAs were detected and analyzed by use of an automatic amino acid analyzer. Aromatic amino acid, branched chain amino acid and Fischer ratio were calculated for each beverage. Individual FAAs showed significant differences between wines and sakes. Sakes abundantly contained almost all FAAs whereas wines had just a little content in some FAAs. Sake were rich in arginine, glycine, alanine, valine, glutamic acid and leucine, while wines were remarkably rich in proline (Pro). Wines showed increased FAA levels in 6 kinds of variables (4-hydroxyproline, 3-methyl histidine, β-alanine, α-aminobutyric acid, Pro and α-aminoadipic acid). In functionally characteristic FAAs, both wines and sakes were considerably abundant in γ-aminobutyric acid and 5-ALA. The total amount of aromatic amino acid and branched chain amino acid were markedly higher in sakes than in wines. These results revealed that there were the apparent different characteristics in FAA profiles between wines and sakes. This difference resulted from fermentation process in wines (single fermentation) and sakes (parallel double fermentation). Forty kinds of FAA profiles are more useful in investigating characteristics of the taste of wines and sakes. In future, detailed FAA analysis has the potential to find functional nutrients such as 5-ALA, whereas other foods generally contain little amount of these FAAs.

Comparative studies on the chemical composition and pharmacological effects of vinegar-processed antler glue modified from Lei Gong Pao Zhi Lun and traditional water-processed antler glue

Ethnopharmacological relevanceAntler glue is a classic medicinal to enhance sexual function in traditional Chinese medicine (TCM), which was first recorded in Shen Nong Ben Cao Jing (Shennong′s Classic of the Materia Medica). Vinegar-processing is a classic method of processing traditional Chinese medicine. The method of preparing antler glue by boiling antlers in vinegar and then concentrating them is recorded in Lei Gong Pao Zhi Lun (Master Lei′s Discourse on Medicinal Processing). In modern times, the typical processing method of antler glue is water extraction and concentration. However, it is not clear whether there is a difference in the effect of these two processing methods on the chemical composition and pharmacological activity of antler glue. Aim of the studyThe Chinese Pharmacopoeia (2020) records that the processing method of antler glue is water extraction and concentration. But Lei Gong Pao Zhi Lun differs in Chinese Pharmacopoeia (2020), which records the processing method of vinegar extraction and concentration. The effect of the two processing methods on antler glue's chemical composition and pharmacological activity is unknown. So this study aimed to elucidate the difference between different processing methods on the chemical composition and the treatment effect on oligoasthenospermia of antler glue. Materials and methodsSo the automatic amino acid analyzer is used to determine the amino acid content of two different processing methods of antler glue. Proteomics was performed to detect the protein components of two different processing methods of antler glue and analyze them. Cyclophosphamide-induced mice models of oligoasthenospermia were used to study the different pharmacological effects of antler glue in two different processing methods. An automatic sperm analyzer observed the quantity and quality of sperm in mice epididymis. Serum sex hormone testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in mice were tested using the enzyme-linked immunosorbent assay (ELISA) kits. Hematoxylin-eosin (H&E) staining was used to analyze pathological alterations in mouse testicular tissue. The transcriptome has been used to reveal the potential mechanism of antler glue in treating oligoasthenospermia. Mitochondrial complex activity assay kits were used to assay the activity of mitochondrial respiratory chain complex I–V in mouse testicular tissue. Western blot was used to determine the expression of related proteins in mouse testicular tissue. ResultsVinegar-processing can increase the alanine, proline, and glycine content in antler glue, reduce the length of protein peptides in antler glue, and produce a variety of unique proteins. Vinegar-processed antler glue (VAG) increased sperm density, sperm survival, sperm viability, and serum sex hormone levels in oligozoospermic mice. It reversed testicular damage caused by cyclophosphamide, and the effects were differently superior to those of water-processed antler glue (WAG). In addition, transcriptomics and related experiments have shown that VAG can increase the expression of Ndufa2, Uqcr11, Cox6b1, and Atp5i genes and proteins in mouse testis, thus promoting adenosine diphosphate (ATP) synthesis by increasing the activity of mitochondrial respiratory chain complexes I, III, IV and V. By promoting the oxidative phosphorylation process to produce more ATP, VAG can achieve the therapeutic effect of oligoasthenospermia. ConclusionVinegar-processing method can increase the content of active ingredients in antler glue. VAG increases ATP levels in the testes by promoting the process of oxidative phosphorylation to treat oligozoospermia.

The Influence of the Lactation Period and the Type of Milk on the Content of Amino Acids and Minerals in Human Milk and Infant Formulas.

(1) Background: This study investigated the effect of the lactation period and the type of infant formula on the content of amino acids and selected minerals in an infant's food; (2) Methods: The study material consisted of breast milk (colostrum, n = 38; transitional milk, mature milk, n = 38) and three types of infant formulas (for first and follow-on feeding). Amino acid content was determined using an automatic amino acid analyzer, while minerals were determined by the atomic absorption spectrometry (AAS) technique; (3) Results: Breast milk and infant formulas contained a full range of essential amino acids. In most cases, the content of individual amino acids and minerals decreased with increasing lactation. In infant formulas, there were higher contents of phenylalanine, glutamic acid, proline, serine, and tyrosine in follow-on milk (p < 0.05). The EAA/TAA ratio in breast milk and infant formulas was similar, but the milk differed in their qualitative composition. Infant formulas contained levels of individual minerals that were several times higher-especially Mg, Ca, Mn, and Fe.; (4) Conclusions: Colostrum is more concentrated, and the level of amino acids and minerals is higher in it; as the milk matures, it decreases. In most cases, the content of individual amino acids and minerals is higher in infant formulas than in human milk, which is established through strict Codex Alimentarius procedures to ensure the proper development of infants.

Bone marrow mesenchymal stem cells response on collagen/hyaluronan/chondroitin scaffold enriched with gentamicin -loaded gelatin microparticles for skin tissue engineering.

The repair and functional reconstruction of large skin defects caused by burn remains an intractable clinical problem. Collagen type I (ColI) was extracted from carp scales and confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis ultraviolet adsorption spectra and automatic amino acid analyzer. Then the scaffolds containing the purified ColI, hyaluronic acid (HA) and chondroitin sulfate (CS) were constructed and examined. The results showed that the scaffold (ColI:CS:HA=9:1:1) had larger pore diameter, porosity, water absorption, degradation rate and tensile strength. gentamycin sulphate (GS) - gelatin microspheres (GMSs) were prepared by emulsion cross-linking method. The drug release study of the ColI-CS-HA-GS/GMSs scaffold with antibacterial property showed a prolonged, continuous, and sustained release of GS. The bone marrow mesenchymal stem cells (BMSCs) were extracted from rat and inoculated into the ColI-HA-CS-GS/GMSs scaffold. The results performed that the scaffold could accelerate proliferation of the BMSCs and wound healing.

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.

Effects of simmering time, salt and sugar addition on the flavour and nutrient release of Morchella soup

AbstractThis study aimed to investigate the effect of different simmering times, salt and sugar addition on the quality of the Morchella soup. The change in the released contents of nutrients and flavour compounds in the Morchella soup within 120 min was studied. The automatic amino acid analyser, solid‐phase microextraction–gas chromatography–mass spectrometry, phenosulphuric acid method, acid–base neutralization principle and 1,1‐dipheny2‐picrylhydrazyl scavenging activity were used to determine the changes in free amino acids, volatile flavour compounds, total sugar, titratable acids and antioxidant activities in the Morchella soup respectively. The results showed that the amount of amino acids, volatile flavour compounds, titratable acid, antioxidant capacity and total sugar in the Morchella soup were significantly higher at 40‐min simmering time than at other simmering times. At 40‐min simmering time, the salt and sugar addition increased the amounts of umami amino acids (54.33%, 23.48%) and total amino acids (40.83%, 20.02%), organic acids (211.6%, 127.74%), sulphur‐containing compounds (130.40%, 237.20%), titratable acids (43.3%, 16.7%), and total sugar (23.8%, 16.7%) and antioxidant activity (87.5%, 23.8%) in the Morchella soup respectively. This study revealed the influence mechanism of simmering time, salt and sugar addition on the Morchella soup and provided a basis for further processing the Morchella soup.

Effects of polyphenols on the gel and digestive properties of Penaeus vannamei myosin after freezing.

Polyphenols could inhibit the freezing-induced denaturation of myosin, and affect its nutritional and functional properties, which have rarely been studied to date. Therefore, the effects of interactions between polyphenols and myosin after freezing on myosin gel and digestive properties were investigated using low field NMR, a texture analyzer, a dynamic rheometer, ultraviolet-visible spectra, scanning electron microscopy, LC-MS/MS, an automatic amino acid analyzer, etc. Hesperetin (HE), dihydroquercetin (DI), salidroside (SA), and mangiferin (MA) increased the water-holding capacity, non-flowable water content, gel strength, texture, storage modulus, and fractal dimensions of the myosin gel, while modifying its leading force. The results of scanning electron microscopy revealed that the surfaces of polyphenol groups were relatively smoother than those of the control group. Meanwhile, the four types of polyphenols under study significantly improved the gastric and gastrointestinal digestibility of myosin. Furthermore, they significantly increased the contents of essential, flavor, and total free amino acids, as well as the unique peptide numbers in myosin digestion products. This work provides reliable guidance for polyphenols to improve protein function and nutritional properties.

A Study of the Ameliorative Effect of Gryllus bimaculatus on Sarcopenia

Purpose: Currently, aging-related sarcopenia is considered a serious problem. However, few studies have addressed the treatment or prevention of sarcopenia using Gryllus bimaculatus . Therefore the present study was carried out to determine whether Gryllus bimaculatus has an ameliorative effect on sarcopenia and to study its applicability as a food for sarcopenia in the elderly or in patients with this condition.Methods: The contents of moisture, crude ash, crude protein, crude fat, carbohydrate and minerals were analyzed. The amino acid and fatty acid compositions were analyzed using an automatic amino acid analyzer and gas chromatography, respectively. Cell viability was measured using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Myostatin expression was investigated in C2C12 cells using a luciferase reporter assay after treatment with a Gryllus bimaculatus extract.Results: The Gryllus bimaculatus powder (GBP), protein extract of Gryllus bimaculatus (PEGB), Gryllus bimaculatus egg (GBE), and egg protein extract of Gryllus bimaculatus (EPGB) were high in essential amino acids, especially branched chain amino acids, and unsaturated fatty acids, and low in carbohydrates. Moreover, Gryllus bimaculatus appeared to have ameliorative effects on sarcopenia by suppressing the mRNA expression of myostatin in C2C12 cells.Conclusion: It is expected that Gryllus bimaculatus will be positive for the development of food materials or to prevent sarcopenia in the elderly or in patients with this condition.

Preparation and Characterization of Flavored Sauces from Chinese Mitten Crab Processing By-Products

To achieve high-value utilization of Chinese mitten crab processing by-products, different types of sauces were prepared using crab legs (CLs) and crab bodies (CBs). Two processing methods, enzymatic hydrolysis and enzymatic hydrolysis coupled with the Maillard reaction, were employed to prepare these sauces. An electronic nose (E-nose) and electronic tongue (E-tongue) were used to measure the changes in the taste and odor, an automatic amino acid analyzer was used to measure the amino acid content, and a headspace solid-phase microextraction GC/MS (HS-SPME-GC/MS) was used to analyze the volatile compounds, qualitatively and quantitatively. The results showed that the sour, bitter, and other disagreeable odors of the enzymatic hydrolysis solution (EHS) were reduced following the Maillard reaction; meanwhile, the umami and saltiness were considerably enhanced. The quantity of free acidic amino acids with an umami and sweet taste in the CL and CB sauces after enzymatic hydrolysis and the Maillard reaction was substantially higher than that in the homogenate (HO). The Maillard reaction solution (MRS) produced more volatile compounds than the HO and EHS, such as aldehydes, pyrazines, ketones, etc. These compounds not only impart a unique flavor but also have antioxidant capabilities, making them a prototype for the high-value utilization of crab processing by-products.