Food research international (Ottawa, Ont.)最新文献

1,3-dioleoyl-2-palmitoylglycerol (OPO) and 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) are two essential types of human milk fat substitutes (HMFS). Their unique fatty acid composition and distribution play a significant role in promoting infant health, making the reaction conversion and acyl migration critical factors for developing efficient preparation methods. Promoting the conversion of the substrate while simultaneously inhibiting acyl migration is crucial for obtaining the desired HMFS products. In this study, we comparatively investigated enzymatic acidolysis and transesterification for HMFS production and revealed enzymatic kinetics as well as acyl migration mechanism during the process. Acyl migration was observed through the lipase-catalyzed mechanism, and the associated free energy changes were analyzed using density functional theory (DFT). The presence of long-chain fatty acids in the synthesis system resulted in intermediates with higher relative free energy during acyl migration. Based on these findings, we propose a novel synthesis strategy consisting of multi-step transesterification and dry fractionation, leveraging the differences in freezing points to minimize acyl migration. The resulting OPO product contains 90.42% oleic acid specifically at the sn-1,3 positions, highlighting its potential application in infant formulas. This study presents a systematic investigation of the kinetics and mechanisms involved in lipase-mediated HMFS production, providing valuable insights for rational synthesis approaches.

Cross-contamination is a major food safety risk during the harvesting and processing of fresh produce, leading to significant losses in global human well-being and the economy. The surface of food contact areas is a high-risk zone for cross-contamination. Therefore, developing an effective antimicrobial coating for food-contact surfaces is essential. This study developed a smart antimicrobial coating that self-regulated in response to environmental conditions, via grafting the stimuli-responsive polymer polyacrylic acid (PAA) and the phage-derived endolysin Lysin81 onto ZnO nanocolumns. During the initial stage of bacterial adhesion, the surface of the nanocolumns exhibited significant mechanical bactericidal activity, while the super hydrophilic PAA layer effectively inhibited bacterial adhesion. At a later stage, when numerous live and dead bacteria adhered to the surface of the nanocolumns, the PAA chains disintegrated, exposing the underlying layer of endolysin that lysed the compromised bacteria. In addition, as the environmental pH increases, the attached dead bacteria can be released once the PAA chains regain their hydrophilicity. This research aimed to apply the antibacterial coating to stainless steel surfaces used in food processing, potentially enhancing surface hygiene and preventing cross-contamination of fresh produce.

Cultivated meat, the process of generating meat in vitro without sacrificing animals, is a promising alternative to the traditional practice of livestock agriculture. However, the success of this field depends on finding sustainable and economical replacements for animal-derived and expensive fetal bovine serum (FBS) that is typically used in cell culture processes. Here, we outline an effective screening process to vet the suitability of microbial lysates to support the growth of immortalized bovine satellite cells (iBSCs) and mackerel (Mack1) cells. We show that easily producible, low-cost whole-cell lysates from Vibrio natriegens can be used to create serum-free media for the long-term growth of iBSCs. The optimized medium, named "VN40" (basal B8 media containing Vibrio natriegens lysate proteins at 40 µg/mL), outperforms previously established serum-free media while maintaining cell phenotype and myogenicity. Overall, this study shows a novel approach to producing serum-free media for cultivated meat production using microbially-derived lysates.

Bio-based and/or biodegradable polymers are being developed and applied as a sustainable and innovative alternative to conventional petroleum-based materials for food packaging applications. From the chemical standpoint, bio-based and/or biodegradable polymers present a complex chemical composition that includes additives, monomers, and other starting substances, but also, oligomers, impurities, degradation products, etc. All these compounds may migrate into the food and can be a hazard to the consumers' health. Thus, identifying potential migrants is crucial to assess the safety of these materials. The analytical methods applied to investigate migrants in bio-based and/or biodegradable polymers are reviewed and commented on. Mostly, gas chromatography or liquid chromatography coupled to mass spectrometry and specifically high-resolution mass spectrometry are the techniques of choice. In addition, a summary of recently published migration studies of chemicals from bio-based and/or biodegradable polymers into food simulants and food is provided. Moreover, current approaches to risk assessment of packaging materials are presented and illustrated with examples. Therefore, this review aims to highlight the chemical safety issues raised by biopolymers for food contact applications, that are often overlooked.

Solar and indoor withering in the manufacturing process of semi-fermented oolong tea are crucial for aroma formation. While the processes have been established through accumulated experience, the underlying mechanisms remain largely unknown. This study identified pairs of gene and volatile organic compound (VOC) that were significantly correlated and up-regulated during solar withering and the first shaking, including lipoxygenase 8 (LOX8) with 3-hexenyl iso-butyrate, terpene synthase 2 (TPS2) with β-ocimene and linalool, as well as tryptophan synthase β-subunit 2 (TSB2) with indole. Besides, two β-glucosidases (β-GH), β-GH1_1 and β-GH3_1, were up-regulated by more than 30-fold in these stages. When comparing the three manufacturing procedures, indole, nerolidol, β-ocimene, benzyl nitrile, and jasmine lactone, were largely accumulated only in the normal process, where both solar withering and shaking were included. These findings provide insights into the regulation of VOC accumulation under stresses during withering, and highlight the importance of specific manufacturing processes in the formation of oolong tea characteristic aroma.

Perchlorate was reported to be taken up by tea (Camellia sinensis L.) plants and mainly stored in leaves. However, the change of contents in perchlorate in fresh tea leaf-made tea and tea infusion remains unclear. Here, we revealed the transfer of perchlorate during green/black tea processing and brewing using UPLC-MS/MS and established a corresponding dietary risk assessment method. The processing factors based on the dry-weight contents of perchlorate during green and black tea processing were in the range of 0.96-1.17. The content of perchlorate was stable throughout tea processing. Perchlorate in made tea was prone to leaching into infusions with an average leaching rate of 74.1 ± 12.6 %. Moreover, risk assessment was developed based on the above processing factor, leaching rate and risk quotient (RQ) method, which contributes to estimating the impact of perchlorate in fresh tea leaves on human dietary exposure via tea drinking.

'Ming guan'(MG), an elite albino cultivar deriving from the progeny of the traditional albino cultivar 'Bai jiguan', is a promising candidate for white tea production due to its favorable amino acid to phenol ratio. In this study, a comprehensive metabolomics analysis using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and headspace solid-phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS) were conducted to reveal the dynamic changes of non-volatile and volatile organic compounds (VOCs) throughout the withering processing of MG white tea. Meanwhile, multivariate statistical analyses were applied to screen for the characteristic components in the flavor and aroma of MG white tea. A total of 625 non-volatile metabolites and 118 VOCs were determined, of which 90 non-volatile metabolites (VIP ≥ 1, FC ≥ 2 or ≤ 0.5) were identified as key flavor components significantly changed throughout the withering process. The relative odor activity value (ROAV) analysis highlighted 22 VOCs (ROAV ≥ 1) with substantial effect on aroma formation, of which geraniol, (E)-2-hexenal, 4-methoxy-benzaldehyde and guaiacol emerging as the most key aroma constituents of MG white tea, endowing MG white tea with fruity and floral odor notes. This study offered a comprehensive investigation into metabolite changes in MG white tea, contributing valuable insights for the innovation of new white tea products utilizing albino tea plant mutants.

Iceberg lettuce is one of the most consumed leafy vegetables, which is often treated by different pesticides against pests and diseases. The aim of this study was to describe the fate of 25 pesticides (16 fungicides, 7 insecticides and 2 herbicides) based on quantitative analysis of the parent compounds and targeted screening of their (bio)transformation products. Mathematical models describing a decrease in pesticide residue levels were proposed for 24 pesticides using a first-order kinetic equation. These models provide the data needed to predict consumer exposure associated with the consumption of conventionally grown iceberg lettuce. At harvest, concentrations of most pesticides were dropped under the established EU maximum residue levels, except for flonicamid, fluazifop and pyriproxyfen. A total of 113 pesticide metabolites and degradation products were detected and tentatively identified in extracts prepared by an optimized extraction procedure, i.e., the acidified QuEChERS method. Several products of reactions such as hydrolysis, dealkylation, dehalogenation and/or oxidation-reduction, originated either from various physicochemical processes, or within Phase I pesticide metabolism were detected. Additionally, numerous conjugates with hexose, malonic acid or acetic acid formed during PhaseII of pesticide metabolism were found. In this way, a deeper understanding of specific pesticide degradation mechanisms is facilitated. In addition, it is easier to track the history of pesticide treatment.

β-Casomorphins (BCMs), food-associated peptides resulting from the proteolytic cleavage of β-casein (β-CN), have been widely investigated for their opioid-like activity. This research aimed to identify the presence of BCM7, BCM6, and BCM5 in different bovine milk-deriving blue cheese types and to describe the intricate mechanisms behind their formation, focusing on their origin from cheese with β-CN A1 and A2 variants. Using nanoLC-ESI-Q-Orbitrap-MS/MS and advanced computational tools, we explored the peptidomes of Bleu d'Auvergne, Gorgonzola, Stilton, and Bergader blue cheeses from milk containing both β-CN A1 and A2 variants. This integrated approach ascertained the occurrence of BCM7 in all cheese samples, although at different concentrations. Evidence demonstrated that all cheeses containing β-CN A1 and A2 variants exhibited proteolysis, resulting in a pronounced BCM7 release because of the concerted activity of multiple Penicillium roqueforti exopeptidases. This study provides insights into the processes underpinning the formation of BCM7, BCM6 and BCM5 in various blue cheese types, identifying putative molecular determinants that might govern the proteolytic release of BCMs from both β-CN A1 and A2 variants as well as the complex interplay between mold peptidases and cheese polypeptide substrates.