Search

The antimicrobial effects of high hydrostatic pressure (HHP) treatments on chill-stored seafood are well-documented, while their impact on the metabolic profile of seafood, especially the metabolome of fish flesh, and remains underexplored. Addressing this gap, this study investigates the effects of HHP on the metabolome of chill-stored rose shrimp by conducting multivariate data analysis based on untargeted proton nuclear magnetic resonance observations. Vacuum-packed rose shrimp samples were subjected to HHP at 0, 400, 500, and 600 MPa for 10 min and then stored at 2-4°C. The microorganism analysis and metabolic analysis were carried out on days 1 and 14. HHP treatment effectively deactivated Lactobacillus spp., Escherichia coli, Pseudomonas spp., total Coliforms, and sulfite-reducing anaerobic bacteria. Consequently, HHP treatment significantly reduced the formation rate of decay-related metabolites, such as hypoxanthine, trimethylamine, and biogenic amines, which exhibited significant accumulation in untreated samples. Multivariate unsupervised analyses provided insights into the overall changes in the metabolite profile induced by HHP. Metabolic pathway analysis revealed several pathways underlying spoilage, including pyruvate metabolism, valine, leucine, and isoleucine biosynthesis, purine metabolism, methane metabolism, glycine, serine, and threonine metabolism, citrate cycle (TCA cycle), glycolysis/gluconeogenesis, alanine, aspartate, and glutamate metabolism, sulfur metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and glyoxylate and dicarboxylate metabolism. Importantly, these pathways underwent alterations due to the application of HHP, particularly at high-pressure levels. In summary, the results unveil the potential mechanisms of HHP effects on chill-stored rose shrimps., (© 2024 The Author(s). Journal of Food Science published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)

Kiwi wine (KW) is tipically made by fermenting juice from peeled kiwifruit, resulting in the disposal of peel and pomace as by-products. However, the peel contains various beneficial compounds, like phenols and flavonoids. Since the peel is edible and rich in these compounds, incorporating it into the fermentation process of KW presents a potential solution to minimize by-product waste. This study compared the aroma and taste profiles of KW from peeled (PKW) and unpeeled (UKW) kiwifruits by combining intelligent sensory technology, GC-MS, and 1 H-NMR. Focusing on aroma profiles, 75 volatile organic compounds (VOCs) were identified in KW fermented with peel, and 73 VOCs in KW without peel, with 62 VOCs common to both. Among these compounds, rose oxide, D-citronellol, and bornylene were more abundant in UKW, while hexyl acetate, isoamyl acetate, and 2,4,5-trichlorobenzene were significantly higher in PKW. For taste profiles, E-tongue analysis revealed differences in the taste profiles of KW from the two sources. A total of 74 molecules were characterized using 1 H-NMR. UKW exhibited significantly higher levels of tartrate, galactarate, N-acetylserotonin, 4-hydroxy-3-methoxymandelate, fumarate, and N-acetylglycine, along with a significantly lower level of oxypurinol compared to PKW. This study seeks to develop the theoretical understanding of the fermentation of kiwifruit with peel in sight of the utilization of the whole fruit for KW production, to increase the economic value of kiwifruit production.

A variety of metabolites contribute to the freshness and taste characteristics of seafood. This study investigated the effects of high hydrostatic pressure (HHP; 400, 500, and 600 MPa) for 10 min) on the metabolome of striped prawn during chilled storage, in relation to microorganisms' development. All treated samples showed lower viable counts throughout storage compared to the untreated counterparts. The limit of acceptability from a microbiological point of view was extended from 9 to as many as 35 days by 600 MPa treatment. Metabolites were quantified by 1 H-NMR through a targeted-untargeted metabolomic approach. Molecules linked to nucleotides' degradation and amines' anabolism suggested an overall freshness improvement granted by HHP. Notably, putrescine and cadaverine were detected only in untreated prawn samples, suggesting the inactivation of degradative enzymes by HHP. The concentration of molecules that influence umami perception was significantly elevated by HHP, while in untreated samples, the concentration of molecules contributing to a sour taste gradually increased during storage. As metabolomics was applied in its untargeted form, it allowed us to follow the overall set of metabolites related to HHP processing and storage, thus providing novel insights into the freshness and taste quality of striped prawn as affected by high hydrostatic pressure.

Latilactobacillus sakei ( L. sakei ), widely used as a starter culture in fermented sausages, is a species adapted to meat environments. Its ability to survive for a long time in such products is due to the exploitation of different metabolic pathways to gain energy (hexose and pentose sugar fermentation, amino acids catabolism, etc.). Since L. sakei demonstrates high phenotypic and metabolic strain biodiversity, in this work, a metabolomic approach was used to compare five strains of different origins. They were cultivated in a defined medium with glucose or ribose at two concentrations, and analyzed through nuclear magnetic resonance ( 1 H-NMR) spectroscopy to monitor amino acid consumptions and accumulation of organic acids and aroma compounds. The results showed that all the strains were able to use arginine, especially when cultivated with ribose, while serine was consumed mainly in the presence of glucose. Aroma compounds (i.e., diacetyl and acetoin) were mainly accumulated in samples with ribose. These aspects are relevant for starter cultures selection, to confer specific features to fermented sausages, and to optimize the fermentations. Moreover, the use of 1 H-NMR allowed the fast identification of different classes of compounds (without derivatization or extraction procedures), providing a powerful tool to increase the knowledge of the metabolic diversity of L. sakei .

Influence of lyophilized okara with varying particle sizes (250-380, 150-180, 120-150, and < 75 μm) on the quality of glucono-δ-lactone-induced tofu was investigated. Adding okara significantly ( p  < 0.05) improved the yield, water-holding capacity, cooking loss, and nutritional value of the conventional tofu. The gel strength and sensory score of the okara-added tofu (OAT) increased with the decreasing of the particle size of okara, and these quality attributes of the OAT were better than those of the conventional tofu, except for the OAT with 250-380 μm okara. The microstructural profile of the OAT with reduced okara particle size was similar to that of the conventional tofu. Theoretically, the addition of okara mainly impacted the interactions among denatured proteins via disulfide bonding and hydrophobic interactions and the sizes of insoluble solid and oil droplet in soymilk, thereby affecting the formation of the gel network and finally the edible quality of tofu. In conclusion, the addition of okara with appropriate particle sizes can remarkably improve the processing quality and nutritional value of tofu, which is beneficial to the reasonable exploration of okara for the producers of soybean products., (© Association of Food Scientists & Technologists (India) 2020.)

The effect of soybean soluble polysaccharide (SSPS) on the formation of glucono-δ-lactone (GDL)-induced soybean protein isolate (SPI) gel was investigated. Electrophoretic analysis showed the SSPS did not change the electrophoretic behavior of SPI during the formation of SPI gel. However, infrared analysis indicated the β-sheet content increased, and the contents of random coil and α-helix decreased in both cooked SPI and SPI gel. The SSPS and SPI might conjugate via the Maillard reaction according to the results of grafting degree, color change, and infrared analyses. The main interactions during the formation of SPI gel changed from non-covalent to electrostatic interaction after adding SSPS. Sulfhydryl group content also increased in both cooked SPI and SPI gel. The water-holding capacity and gel strength of SPI gel decreased as the SSPS concentration increased. Larger aggregate holes were observed in the microstructure of SPI gel at higher SSPS concentration. Thus, SSPS could covalently conjugate with SPI and influence the formation of hydrogen bonds, disulfide bonds, and electrostatic interaction among SPI molecules to eventually form a loose gel network.

To improve the quality of whole soybean curd (WSC), effects of compound coagulants consisting of calcium chloride (CaCl 2 ) and transglutaminase (TGase) were investigated. The results showed that TGase modified the water distribution and reduced the cooking loss of WSC, accompanying with increased water holding capacity. The bloom value of WSC was upgraded as the TGase concentration increased. Although certain sensory parameters showed different scores in groups, the overall acceptability of 1500 ppm group was the highest. TPA test suggested that hardness, springiness and chewiness were promoted by TGase significantly. Smooth appearance of WSC was observed, resulting from the transformation of microstructure. Protein subunits of 7Sα', 7Sα, 7Sβ, 11SA3, 11S acidic, and 11S basic proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, band intensity of protein subunits declined at storage and cooking phase, indicating that crosslinking of proteins was still in progress. In conclusion, the addition of TGase improved the quality of CaCl 2 -induced WSC and could be used to facilitate the production of this new type of soybean product.

Modification of functional properties by glycosylating with polysaccharides is an effective solution to improve the internal disadvantages of native proteins. Generally, protein glycosylation belongs to the first stage of the Maillard reaction in essence. Dry-heating, wet-heating, and their combination are the major methods for the preparation of protein-polysaccharide conjugates (PPC). Spectrophotometry, spectroscopy, electrophoresis, calorimetry, chromatography, and mass spectrometry are confirmed to be the most effective methods for the identification of PPC. After glycosylation, functionalities of the native protein, including solubility, rheological properties, emulsifying properties, foaming properties, gel property, film-forming properties, thermal stability, antioxidant activity, allergenicity, and antibacterial properties, are improved. The PPC is extensively used as an encapsulation or a delivering material in order to improve the bioaccessibility of bioactive compounds in food system. Some new applications in food processing could be explored using PPC as an ingredient based on the improved functional properties, such as 3-dimensional printing food, gelled food, and colloid food. Furthermore, the model of protein glycosylation and the application of PPC in food processing could be extended to other protein modification to broaden the exploitation of native protein resource for the processing of novel foods.