Microbiological and chemical changes of shrimp Acetes vulgaris during Kapi production.

Microbiological and chemical changes in shrimp Acetes vulgaris during production of Kapi (salted shrimp paste of Thailand) including salting, drying and fermentation were monitored. Moisture content of samples decreased rapidly after salting and drying steps. The lower water activity was found in the final product (0.694). The pH decreased within the first 10 days of fermentation and continuously increased as fermentation progressed. Protein underwent degradation throughout Kapi production as indicated by increasing TCA-soluble peptides and degree of hydrolysis. The increases in peroxide value as well as thiobarbituric acid reactive substances value revealed that lipid oxidation occurred throughout all processes. Total viable count, halophilic, proteolytic and lipolytic bacteria counts increased continuously during Kapi production, while lactic acid bacteria count slightly decreased at the final stage of fermentation. Thus, proteolysis and lipolysis took place throughout Kapi production, and contributed to the characteristics of finished product. These changes were governed by both endogenous and microbial enzymes.

Lipid and Volatile Profiles of Various Goat Primal Cuts: Aspects of Nutritional Value and Flavor/Taste Attributes.

The lipid and volatile profiles of goat primal cuts (shoulder, rib, loin, breast, and leg), as well as their potential impact on nutritional and flavor/taste attributes, were investigated. The breast cuts had the lowest protein but the highest fat content. Triacylglycerol was the predominant lipid in all cuts (82.22-88.01%), while the breast cuts had the lowest triacylglycerol and the highest diacylglycerol and free fatty acids. Also, the highest unsaturated fatty acid (UFA), both monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), was obtained in the breast cuts. These findings correlated well with the highest peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) value. The volatile profiles of the various grilled cuts indicated that the breast and leg cuts had similar volatiles, with higher amounts of alcohol, aldehyde, ketone, and ester than others, which could explain the flavor oxidation by lipid and off-flavors in spoiled meat. While the shoulder, rib, and loin cuts had higher amounts of nitrogen-containing compounds. The highest sulfur-containing and hydrocarbon compounds were also observed in the shoulder cuts, which are mainly formed during the Maillard reaction and responsible for the cooked meat flavor. This investigation revealed that each cut of goat meat has a varied composition, especially in lipids and volatile compounds. Thus, meat quality differs in terms of nutritional aspects and flavor/taste characteristics, enabling consumers to select nutritious or proper cuts for their cooking to achieve the most satisfaction from goat meat consumption.

The impact of hot-air oven drying combined with Bacillus subtilis KC3 inoculation on quality characteristics and microbial profiles of salted shrimp paste.

This study used hot-air oven drying with Bacillus subtilis KC3 inoculation to improve shrimp paste production. The fermentation rate, quality characteristics, as well as microbial profiles, were compared to those produced using sun-drying with/without inoculation. B. subtilis inoculation increased the degree of hydrolysis of shrimp paste (22.3-32.1 %) during fermentation, compared to those without inoculation (12.7-25.4 %), regardless of different drying methods (p < 0.05). The result corresponded to the faster development of shrimp paste characteristics, particularly color and browning intensity of inoculated samples when fermented for the same duration. More abundant halophilic, proteolytic, and lipolytic bacteria (p < 0.05) were also obtained in inoculated samples, confirming accelerated fermentation. Interestingly, there was no difference in proximate composition, pH, and aw among samples (p > 0.05), which were still in the range regulated by the product's standard. However, the protein and lipid degradation products such as nitrogen contents, 5'-nucleotides, free fatty acids or TBARS values, varied among samples, potentially influencing the release of desirable flavor precursors to a certain extent. The inoculation increased microbial richness and evenness/uniformity, according to next-generation sequencing analysis on microbiota profiles. Pearson's correlation also revealed that these microbiota profiles were correlated with several desirable quality characteristics to varying degrees. Thus, combining the inoculation with B. subtilis KC3 can enhance shrimp paste fermentation and quality when produced using an alternative hot-air oven while maintaining quality characteristics. The findings suggested the possibility of achieving a more efficient and consistent production process for shrimp paste.

Proteomic profiles revealed enzymatic activities associated with the flavor formation of salted shrimp paste influenced by Bacillus subtilis K-C3 inoculation.

Enzymatic proteomic profiles were examined to comprehend the predominant enzymes involved in the flavor development of salted shrimp paste influenced by Bacillus subtilis K-C3 inoculation (Inoc), compared to those without inoculation (CON). Inoc showed greater proteolytic, lipolytic, and chitinolytic activities than CON (P < 0.05) throughout 30 days of fermentation, indicating B. subtilis's ability to accelerate the fermentation rate and render distinctive flavor profiles to shrimp paste. Among 50 differential abundance proteins (DAPs), 24 DAPs were identified as potential key regulating enzymes, with a P-value < 0.05 and |FC| > 0.50, indicating their significance and regulating capacity within specific metabolic pathways. Notably, 27 and 23 DAPs were up-regulated in Inoc and CON, respectively. Moreover, gene ontology (GO) enrichment analysis revealed that hydrolases, involved in carbohydrate metabolic processes and proteolysis, were the most differentiating pathways between Inoc and CON. Both samples exhibited different flavor profiles. A greater abundance of N-containing volatile compounds with a lower total abundance of aldehydes, ketones, alcohols, and acids could suggest a more favorable flavor in Inoc, compared to CON. Principal component analysis (PCA) revealed a positive correlation between L-ascorbate peroxidase, carboxypeptidase, and tripeptidyl peptidase sed2, with proteolytic and lipolytic activities in Inoc (P < 0.05). Meanwhile, acids and alcohols were positively correlated with CON. Therefore, B. subtilis inoculation could produce a distinctive flavor with a desirable sensory perception of shrimp paste regarding its ability to release extracellular enzymes/proteins. B. subtilis K-C3 inoculation could be suggested in the production of shrimp paste to improve its flavor characteristics.

A comprehensive study of sous-vide cooked Korat chicken breast processed by various conditions: texture, compositional/structural changes, and consumer acceptance.

Korat chicken (KC) is a slow-growing crossbreed renowned for its excellent growth and firm texture. This study investigated the effect of various sous-vide (SV) conditions (60 and 70°C, 1-3 h) on their texture, protein structure and degradation, as well as consumer acceptability, with the traditional boiling served as control. Texture showed significant improvement under all SV conditions compared to the control, as demonstrated by increased water holding capacity (WHC), cooking loss, and decreased shear force, hardness, and chewiness (P < 0.05). These changes corresponded to the higher sensory scores (P < 0.05). Among the SV samples, increased temperatures and longer cooking times led to higher degradation of myofibrils and connective tissue, as evidenced by a decrease in water-, salt-soluble proteins, and soluble collagen (P < 0.05). These findings aligned with the scanning electron microscopy (SEM) results, which showed a looser muscle structure in the meat under more intense cooking conditions. Based on synchrotron radiation-based Fourier transform infrared (SR-FTIR) results, a gradual increase in antiparallel forms within the amide I bands (1,700-1,600 cm-1) of the total spectra with higher temperature and longer cooking times was observed (P < 0.05), while the fluctuations were observed in the changes of α-helix, ß-sheet, and ß-turn structures. This suggested that the antiparallel structure represented a looser configuration developing during intense SV cooking. Combined with the principal component analysis (PCA) results, the findings indicated that the suitable SV condition for KC breast meat was 70°C for varying durations (1-3 h), as it showed the strongest correlation with sensory scores, particularly in terms of tenderness. In summary, these findings provided a better understanding of molecular changes and discovered SV conditions to enhance the texture quality of the KC meat.

Characterization of the Non-Volatiles and Volatiles in Correlation with Flavor Development of Cooked Goat Meat as Affected by Different Cooking Methods.

Thai-Native×Anglo-Nubian goat meat cooked by grilling (GR), sous vide (SV), and microwave (MW), was compared to fresh meat (Raw) in terms of flavor development. Non-volatile [i.e., free amino acids, nucleotide-related compounds, taste active values (TAVs) and umami equivalency, sugars, lipid oxidation, Maillard reaction products] and volatile compounds, were investigated. Notably, inosine monophosphate and Glu/Gln were the major compounds contributing to umami taste, as indicated by the highest TAVs in all samples. Raw had higher TAVs than cooked ones, indicating that heat-cooking removes these desirable flavor and taste compounds. This could be proportionally associated with the increase in aldehyde, ketone, and nitrogen-containing volatiles in all cooked samples. GR showed the highest thiobarbituric acid reactive substances (1.46 mg malonaldehyde/kg sample) and browning intensity (0.73), indicating the greatest lipid oxidation and Maillard reaction due to the higher temperature among all cooked samples (p<0.05). In contrast, SV and Raw exhibited similar profiles, indicating that low cooking temperatures preserved natural goat meat flavor, particularly the goaty odor. The principal component analysis biplot linked volatiles and non-volatiles dominant for each cooked sample to their unique flavor and taste. Therefore, these findings shed light on cooking method selection based on desirable flavor and preferences.

Optimization of ultrasonic assisted ethanolic extraction for natural pigments from butterfly pea flower applied in Thai dessert using Box-Behnken approach.

Butterfly pea is a natural color source used in food and dessert. This study optimized ultrasound-assisted extraction with ethanol for pigments from butterfly pea flowers (BPF) using a Box-Behnken method. Key factors explored were solid-to-solvent ratio, ultrasound extraction time, and ethanol concentration. The extracted compounds were evaluated for extraction yield (EY), total phenolic content (TPC), total anthocyanin content (TAC), and DPPH antioxidant activity. EY increased significantly with reduced ethanol concentration. Optimal conditions were predicted and experimentally validated. BPF extracts showed distinct absorption wavelengths at different pH levels. BPF extract was used in coconut milk jelly, resulting in the lowest b* value. These findings highlight the value of optimal ultrasonic-assisted extraction for enhancing BPF's natural colorant extraction and promoting sustainable use in food and dessert applications.

Metabolomic profiles and compositional differences involved in flavor characteristics of raw breast meat from slow- and fast-growing chickens in Thailand.

This study aimed to differentiate the flavor characteristics of raw chicken breast meat from Thai slow-growing breeds (NC: native chicken, and KC: Korat/crossbred chicken) and fast-growing broilers (BR: broiler chicken) by using NMR-based metabolomic approaches along with multivariate data analysis. Chemical compounds related to chicken's flavor including free amino acids (FAA), ATP and its related compounds, sugars, as well as volatile compounds (VOC), were also investigated. BR had the highest total FAAs, followed by NC and KC (P < 0.05). In contrast, the accumulations of ATP degradation products, particularly ADP and IMP, were found at higher levels in the NC and KC (P < 0.05), while the highest total reducing sugars were noted in the KC (P < 0.05). Most VOCs found in the fresh breasts were products from the degradation of lipids, especially through lipid oxidation, which was found in varied types and proportions among samples. Not only chemical compounds but varying amounts of metabolites among samples were also detected. Apart from 21 identified metabolites, Glu, Gln, and betaine were the most prevalent in all samples with VIP > 1.00. Among 19 metabolic pathways, the most important pathways (P-value < 0.05, FDR < 0.05, impact > 0.05) were discovered to differentiate the flavor of raw chicken breast meat from various breeds. These metabolic pathways included (1) Ala, Asp and Glu metabolism; (2) D-Gln and D-Glu metabolism; (3) Purine metabolism; (4) ß-Ala metabolism; (5) Aminoacyl-tRNA biosynthesis; (6) Nicotinate and nicotinamide metabolism; (7) Pyrimidine metabolism. Interestingly, based on the principal component analysis plot and partial least square-discriminant analysis (R2 = 0.9804; Q2 = 0.9782), NC and KC were clustered in the same area and discriminated from BR, indicating their similar flavor characteristics and metabolic profiles. Therefore, the findings could comprehend and distinguish the flavor of chicken breast meat of slow- from fast-growing chicken breeds based on their chemical characteristics and metabolite profiles.

Exploration of nutritional and bioactive peptide properties in goat meat from various primal cuts during in vitro gastrointestinal digestion and absorption.

OBJECTIVE: This research aims to explore the nutritional and bioactive peptide properties of goat meat taken from various primal cuts, including the breast, shoulder, rib, loin, and leg, to produce these bioactive peptides during in vitro gastrointestinal (GI) digestion and absorption. METHODS: The goat meat from various primal cuts was obtained from Boer goats with an average carcass weight of 30±2 kg. The meat was collected within 3 h after slaughter and was stored at -80°C until analysis. A comprehensive assessment encompassed various aspects, including the chemical composition, cooking properties, in vitro GI digestion, bioactive characteristics, and the bioavailability of the resulting peptides. RESULTS: The findings indicate that the loin muscles contain the highest protein and essential amino acid composition. When the meats were cooked at 70°C for 30 min, they exhibited distinct protein compositions and quantities in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, suggesting they served as different protein substrates during GI digestion. Subsequent in vitro simulated GI digestion revealed that the cooked shoulder and loin underwent the most significant hydrolysis during the intestinal phase, resulting in the strongest angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition. Following in vitro GI peptide absorption using a Caco-2 cell monolayer, the GI peptide derived from the cooked loin demonstrated greater bioavailability and a higher degree of ACE and DPP-IV inhibition than the shoulder peptide. CONCLUSION: This study highlights the potential of goat meat, particularly cooked loin, as a functional meat source for protein, essential amino acids, and bioactive peptides during GI digestion and absorption. These peptides promise to play a role in preventing and treating metabolic diseases due to their dual inhibitory effects on ACE and DPP-IV.

Investigating the Effect of Various Sous-Vide Cooking Conditions on Protein Structure and Texture Characteristics of Tilapia Fillet Using Synchrotron Radiation-Based FTIR.

The effects of various sous-vide (SV) cooking conditions (50-60℃, 30-60 min) on physicochemical properties related to the texture characteristics, protein structure/degradation, and sensory acceptability of tilapia fillet (Oreochromis niloticus) were investigated. With an increasing temperature and processing time of SV cooking, protein degradation (of both myofibrils and connective tissue) was more pronounced, as evaluated by the decrease in water- and salt-soluble proteins, total collagen, as well as the changes in the ratio of secondary protein structures (α-helix, ß-sheet, ß-turn, etc.), which were determined by synchrotron-FTIR (SR-FTIR). These degradations were associated with the improvement of meat tenderness, as estimated by shear force and texture profile analyzer (TPA) results. Among all SV conditions, using 60 ℃ for 45 min seems to be the optimal condition for tilapia meat, since it delivered the best results for texture characteristics and acceptability (p < 0.05). Moreover, principal component analysis (PCA) results clearly demonstrated that the highest texture-liking score of this condition was well associated with the intensity of ß-sheets, which seem to be the crucial component that affected the texture of SV-cooked tilapia more so than other parameters. The findings demonstrated the potential of SR-FTIR to decipher the biomolecular structure, particularly the secondary protein structure, of SV-cooked tilapia. This technique provided essential information for a better understanding of the changes in biomolecules related to the textural characteristics of this product.

Effect of fed dietary yeast (Rhodotorula paludigena CM33) on shrimp growth, gene expression, intestinal microbial, disease resistance, and meat composition of Litopenaeus vannamei.

Yeast is a health-promoting and bio-therapeutic probiotic that is commonly used in aquaculture. Rhodotorula paludigena CM33 can accumulate amounts of intracellular carotenoids and lipid, which are regarded as nutritionally beneficial compounds in various aspects. The aim of this study was to evaluate the impact of different levels of R. paludigena CM33 (RD) incorporated in a dietary composition at 0% (control), 1% (1% RD), 2% (2% RD), and 5% (5% RD) on the growth of shrimp (Litopenaeus vannamei), their immune-related gene expression, intestinal health, resistance to Vibrio parahaemolyticus (VPAHPND) infection, and meat composition. The results showed significant improvements in the specific growth rate, weight gain, and survival of shrimp fed with 1% RD, 2% RD, and 5% RD, which were higher than the control group after 4 weeks of administration. The administration of 5% RD group resulted in a decrease in cumulative mortality upon VPAHPND challenge when compared to the control group. Furthermore, the expression levels of immune-responsive genes, including proPO system (prophenoloxidase-2: PO2), antioxidant enzyme (superoxide dismutase: SOD, glutathione peroxidase: GPX, and catalase: CAT), JAK/STAT pathway (signal transducer and activator of transcription: STAT, gamma interferon inducible lysosomal thiol reductase: GILT), IMD pathway (inhibitor of nuclear factor kappa-B kinase subunit beta and epsilon: IKKb and IKKe), and Toll pathway (Lysozyme) genes, were up-regulated in the 5% RD group. In the context of microbiota, microbiome analysis revealed that the main phyla in shrimp intestines were Proteobacteria, Firmicutes, Bacteroidota, Campilobacterota, Actinobacteriota, and Verrucomicrobiota. At the genus level, Vibrio was found to be reduced in the 5% RD group, whereas the abundance of potentially beneficial bacteria Bifidobacterium was increased. The 5% RD group showed a significant increase in the levels of crude protein and crude lipid, both of which are essential nutritious components. Our results show the capability of R. paludigena CM33 as a probiotic supplement in shrimp feed in improving growth, antimicrobial responses against VPAHPND, and meat quality by increasing protein and lipid content in shrimp.

Development of Flavor and Taste Components of Sous-Vide-Cooked Nile Tilapia (Oreochromis niloticus) Fillet as Affected by Various Conditions.

This study aims to shed light on the association between non-volatile and volatile compounds related to flavor/taste characteristics as well as sensory acceptability of Nile tilapia fillet (Oreochromis niloticus) cooked by various sous-vide (SV) conditions (50−60 ℃, 30−60 min), with fish cooked with boiling water used as control. Higher temperatures and longer processing times of SV cooking led to greater protein and lipid oxidation as indicated by the increase in total sulfhydryl (-SH), carbonyl, free fatty acid (FFA) contents as well as peroxide values (PV) and thiobarbituric acid reactive substance (TBARS) values. The differences in flavor/taste components including adenosine triphosphate (ATP)-related compounds, free amino acids (FAAs) and volatiles were also obtained, which directly affect sensory acceptability as evaluated by using the hedonic scale. Based on principal component analysis (PCA) results, the acceptability score was strongly correlated with inosine monophosphate (IMP) and acetoin, which seem to be the most crucial flavor enhancers for cooked tilapia. Among all samples, tilapia processed at 60 °C for 45 and 60 min, which contained significantly higher IMP and acetoin (p < 0.05) than others, had significantly higher flavor-liking and overall-liking scores, with a more than 7.5 meaning for high acceptability (p < 0.05), indicating the optimal SV conditions for tilapia fillet. Overall, the present finding indicated that the SV-cooking technique, at the optimal conditions, can improve the meat quality of cooked fish, in terms of flavor/taste characteristics, compared with traditional cooking (control).

The Use of Sodium Benzoate on Shelf-Life and Quality Attributes of Dried Chili Fish Paste Stored in Different Packaging Containers.

This study was carried out to assess the quality changes and shelf-life of dried chili fish paste treated with 0.1% sodium benzoate (SB) and stored in various packaging containers, including polypropylene (PP+SB), polyethylene-terephthalate (PET+SB), and LLDPE-aluminum Ziplock bag (ZL+SB) during 20-week storage at room temperature (25-28 °C) compared with samples without preservatives (PP, PET, and ZL). The result found that samples treated with 0.1% SB exhibited slower rate of quality changes throughout storage, including pH, browning index, oxidation products, as well as microorganisms, etc. These samples can store at room temperature for at least 20 weeks without any spoilage. Moreover, the sensorial scores of them, assessed by 50 untrained panelists who were familiar with this product, were more than 7.0 in all aspects, for example, color, flavor, and texture. In contrast, samples without preservatives, which revealed the higher rate of the changes in all quality characteristics, underwent spoilage during 20-week storage at different times depending on the packaging container. The shelf-life of PP, PET, and ZL were 6, 10, and 10 weeks, respectively, as indicated by the excess of total microorganisms (>1.00 × 104 CFU/g sample). Overall, the results indicated that using sodium benzoate at the level of 0.1% can effectively extend the shelf-life of dried chili fish paste for at least 5 months with prime quality.