Nanocarrier system: An emerging strategy for bioactive peptide delivery.

Compared with small-molecule synthetic drugs, bioactive peptides have desirable advantages in efficiency, selectivity, safety, tolerance, and side effects, which are accepted by attracting extensive attention from researchers in food, medicine, and other fields. However, unacceptable barriers, including mucus barrier, digestive enzyme barrier, and epithelial barrier, cause the weakening or the loss of bioavailability and biostability of bioactive peptides. The nanocarrier system for bioactive peptide delivery needs to be further probed. We provide a comprehensive update on the application of versatile delivery systems for embedding bioactive peptides, including liposomes, polymer nanoparticles, polysaccharides, hydrogels, and self-emulsifying delivery systems, and further clarify their structural characterization, advantages, and disadvantages as delivery systems. It aims to provide a reference for the maximum utilization of bioactive peptides. It is expected to be an effective strategy for improving the bioavailability and biostability of bioactive peptides.

Endogenous Peptides Identified in Soy Sauce Aroma Style Baijiu Which Interacts with the Main Flavor Compounds during the Distillation Process.

Endogenous peptides in Chinese baijiu have been recently reported. However, little information is available on their correlation with the main flavor substances. One hundred and forty-six peptides, consisting of more bitter amino acids and key amino acids responsible for bioactivity, were identified in tail liquor using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Additionally, the content of endogenous peptides increased gradually with distillation time, showing a high negative correlation with total esters (r = -0.929) and total alcohol (r = -0.964) but presented a moderate positive correlation with the total acid content (r = 0.714). The results of the correlation analysis between them were further proved by molecular docking, which showed that these endogenous peptides in baijiu interacted with the main flavor substances via hydrogen bonds. This study clarifies the dynamic changes of endogenous peptides during distillation and provides a theoretical reference for the relationship between these peptides and the main flavor substances.

Electrochemical esterification in distilled liquor via gold catalysis and its application for enhancing ester aroma of low-alcohol liquor.

The development of low-alcohol liquor (Baijiu) can represent a tool to solve the problems of excessive alcohol intake. However, low-alcohol liquor has an insufficient ester aroma and a bland taste due to the alcohol dilution process. This study proposes an electrochemical catalysis technology to catalyze the esterification reaction between the acid and alcohol in liquor, thereby enhancing the ester aroma of low-alcohol liquor. In the electrochemical conversion process, the gold electrode with a certain potential promotes the formation of carbocation intermediate from corresponding carboxylic acid, thereby improving the esterification reaction efficiency. The key finding is that the total ester content of liquor treated using this technology is increased by more than 20%, and a strong ester aroma is attained. This study clarifies the electrocatalytic mechanism of the esterification reaction in liquor, and provides a new idea for making low-alcohol liquor become more attractive for aroma and taste aspects trying to obtain an alternative product contributing to the public health.

Correlation between the redox activity of Polygonum multiflorum extract and its extraction technology with Chinese liquor (Baijiu): An electrochemistry-based study.

Elucidating the pharmaceutical mechanisms behind traditional Chinese medicine (TCM) is the key to promote its modernization process. In China, soaking TCM in liquor has a history of thousands of years, and many TCMs have to be processed into liquor before they can be used to treat diseases. Chinese liquor (Baijiu) contains more than 2,000 trace components, the interaction mechanism between TCM and Baijiu still remains unclear, making TCM a "mystery". The TCM industry commonly employs chromatographic and spectrographic technology to investigate the redox activity of TCM substances. However, only investigating the redox differences in specific active substances cannot provide a complete understanding of the redox activity of TCM substances. Thus, we employed the electrochemical approach to study the overall redox activity of substances in TCM in situ. The key result is that the redox substances in Baijiu function as a mediator for the redox reaction of Polygonum multiflorum extract. The redox efficiency of the extract is enhanced because of the faster electron transferability of the redox mediator in Baijiu.

Succession patterns of aroma components during brewing process of broomcorn millet (Panicum miliaceum L.) Huangjiu.

The flavor of Huangjiu is closely related to its brewing technology. Patterns of aroma component succession during the process of brewing broomcorn millet Huangjiu were investigated by solvent-assisted flavor evaporation combined with gas chromatography-mass spectrometry and chemometrics. During fermentation, esters, alcohols, acids, ketones, acetals, sulfur compounds, furans, and lactones were formed mostly in the chief fermentation stage; nitrogenous and phenolic compounds increased in the primary fermentation stage and then decreased; aldehydes decreased after fermentation started; and terpenes decreased after five days. During aging, acids, alcohols, ketones, lactones, phenols, and nitrogenous and sulfur compounds first decreased and then increased; and esters, acetals, aldehydes, and furans always increased, while terpenes decreased continuously. Key odorants, including acetic acid, 3-methylbutanoic acid, 1,1-diethoxyethane, and 3-methylbutanal, were produced in large quantities in the primary fermentation stage; ethyl lactate, ß-phenylethanol, and 2/3-methyl-1-butanol were generated in large quantities in the chief fermentation stage; and sotolon and methional were generated in the aging stage. This study is of great significance for the quality control of Huangjiu production.

Sensomics-assisted flavor decoding of coarse cereal Huangjiu.

Huangjiu is one of China's national alcoholic beverages. The key odorants in four coarse cereal Huangjius (CCH) were identified by sensomics approach. Eighty-eight odorants were identified using solvent-assisted flavor evaporation combined with gas chromatography-olfactometry/spectrometry and aroma extract dilution analysis. Four aroma recombinates showed good similarities to the corresponding original aroma profiles (93.27-96.97%). Partial least squares regression analysis predicted vanillin and ß-damascenone were the main causes of the aroma differences in the four CCHs. For the first time, omission and addition tests showed that ß-damascenone caused the sweet and tea leaf aromas, whereas hexanal, nonanal, and 2-methyl-3-(methyldisulfanyl)furan contributed to the cooked grain aroma. Finally, 2-phenylethanol, ethyl (E)-3-phenyl-2-propenoate, ethyl 3-phenylpropanoate, vanillin, 3-(methylsulfanyl)propanal, γ-nonalactone, sotolon, ß-damascenone, hexanal, nonanal, and 2-methyl-3-(methyldisulfanyl)furan were confirmed as the key odorants in the CCHs. 2-Methyl-3-(methyldisulfanyl)furan was a newly identified key odorant in Huangjiu.

Correction to "Influence of Electrochemical Oxidation on the Maturation Process of the Distilled Spirit".

[This corrects the article DOI: 10.1021/acsomega.0c02090.].

Effects of ultrasound-assisted low-concentration chlorine washing on ready-to-eat winter jujube (Zizyphus jujuba Mill. cv. Dongzao): Cross-contamination prevention, decontamination efficacy, and fruit quality.

Wash water is circulated for use in the minimal processing industry, and inefficient disinfection methods can lead to pathogen cross-contamination. Moreover, few disinfection strategies are available for ready-to-eat fruits that do not need to be cut. In this study, the use of chlorine and ultrasound, two low-cost disinfection methods, were evaluated to disinfect winter jujube, a delicious, nutritious, and widely sold fruit in China. Ultrasound treatment (28 kHz) alone could not decrease the cross-contamination incidence of Escherichia coli O157:H7, non-O157 E. coli, and Salmonella Typhimurium, and free chlorine treatment at 10 ppm decreased the incidence from 55.00% to 5.00% for E. coli O157:H7, 65.00% to 6.67% for non-157 E. coli, and 70.00% to 6.67% for S. Typhimurium. The cross-contamination incidence was completely reduced (pathogens were not detected in sample) when the treatments were combined. The counts of aerobic mesophiles, aerobic psychrophiles, molds, yeasts, and three pathogens in the group subjected to combination treatment (28 kHz ultrasound + 10 ppm free chlorine) were significantly lower than those in the control, chlorine-treated, and ultrasound-treated groups during storage (0-7 d at 4 °C). Analysis of weight loss, sensory quality (crispness, color, and flavor), instrument color (a*/b*), soluble matter contents (total soluble solids, reducing sugar, total soluble sugar, and titratable acid), and nutritional properties (ascorbic acid and polyphenolic contents) indicated that treatment with ultrasound, chlorine, and their combination did not lead to additional quality loss compared with properties of the control. Additionally, the activities of phenylalanine ammonia-lyase and polyphenol oxidase were not significantly increased in the treatment group, consistent with the quality analysis results. These findings provide insights into disinfection of uncut ready-to-eat fruits using a minimum dose of disinfectant for cross-contamination prevention under ultrasonication. The use of ultrasound alone to decontaminate fresh produce is accompanied by a high risk of pathogen contamination, and the use of sanitizers to decrease cross-contamination incidence is recommended.

Elucidating metal ion-regulated flavour formation mechanism in the aging process of Chinese distilled spirits (Baijiu) by electrochemistry, ICP-MS/OES, and UPLC-Q-Orbitrap-MS/MS.

Elucidating the organometallic interactions in Baijiu will promote a deeper understanding of the flavour formation mechanism during Baijiu aging. However, the organometallic interactions during aging are difficult to explore because the concentration and status of metals in Baijiu samples are affected by other substances (such as organic acids), and the concentrations of these substances also change dynamically. Hence, the flavour formation mechanism of aged Baijiu was investigated based on a multi-method analysis (i.e. electrochemistry, ICP-MS/OES, and UPLC-Q-Orbitrap-MS/MS), which enabled us to solve the difficulty above. The key finding is that, in the aging period, the organic acids induce the transformation of the metal ion state from the complex state to the free state. As a result, the flavour compound (i.e. the esters) contents in aged Baijiu are regulated by the free metal ion-catalyzed reactions.

Use of Acetic Acid to Partially Replace Lactic Acid for Decontamination against Escherichia coli O157:H7 in Fresh Produce and Mechanism of Action.

Escherichia coli O157:H7 is frequently detected in ready-to-eat produce and causes serious food-borne diseases. The decontamination efficacy of lactic acid (LA) is clearly established. In this study, LA was mixed with acetic acid (AA) to reduce costs while achieving consistent or better inhibitory effects. Time-kill curves and inoculation experiments using fresh-cut spinach and arugula indicated that 0.8%LA+0.2%AA shows similar antibacterial effects to those of 1%LA. To determine whether 1%LA and 0.8%LA+0.2%AA exert antibacterial effects by similar mechanisms, proteomics analysis was used. The proteins related to macromolecule localization, cellular localization, and protein unfolding were uniquely altered after the treatment with 1%LA, and the proteins related to taxis, response to stress, catabolic process, and the regulation of molecular function were uniquely altered after the treatment with 0.8%LA+0.2%AA. Based on these findings, combined with the results of a network clustering analysis, we speculate that cell membrane damage is greater in response to LA than to 0.8%LA+0.2%AA. This prediction was supported by cell membrane permeability experiments (analyses of protein, nucleotide, ATP, and alkaline phosphatase leakage), which showed that LA causes greater membrane damage than 0.8%LA+0.2%AA. These results provide a theoretical basis for the application of an acid mixture to replace LA for produce decontamination.

Combination of ozone and ultrasonic-assisted aerosolization sanitizer as a sanitizing process to disinfect fresh-cut lettuce.

Reduction of sanitizer dosage and development of non-immersion disinfection methods have become major focuses of research. Here, we examined the disinfection efficacy of combining gaseous ozone (4 and 8 ppm) with aerosolized oxidizing sanitizer [sodium hypochlorite (SH, 100 and 200 ppm)] and aerosolized organic acid [acetic acid (AA, 1% and 2%) and lactic acid (LA, 1% and 2%)]. Notably, 1% AA and 4 ppm gaseous ozone were ineffective for disinfecting Salmonella Typhimurium, and treatment with 1% AA + 8 ppm ozone caused browning of lettuce leaves and stimulated increases in aerobic mesophilic count (AMC), aerobic psychrotrophic count (APC), S. Typhimurium, and Escherichia coli O157:H7. Treatment with 2% LA + 8 ppm ozone resulted in the lowest S. Typhimurium, E. coli O157:H7, Listeria monocytogenes, AMC, APC, and molds and yeasts during storage (0-7 days at 4 °C). Quality analysis indicates that LA + 8 ppm ozone and SH + 8 ppm ozone did not negatively affect L*, a*, b*, polyphenolic content, weight loss, and sensory properties; however, the levels of two individual phenolic compounds (3,4-dihydroxybenzoic acid and vanillin), responsible for phenylpropanoid synthesis, were significantly increased after treatment with 2% LA + 8 ppm ozone. These findings provided insights into the use of LA combined with gaseous ozone for application in disinfecting fresh produce.

Elucidating oxidation-based flavour formation mechanism in the aging process of Chinese distilled spirits by electrochemistry and UPLC-Q-Orbitrap-MS/MS.

The oxygen-based oxidation process is leading toward the understanding of the flavour formation mechanism of aged Baijiu. However, the oxygen-based oxidation process in Baijiu aging is difficult to explore because of (1) the composition of Baijiu produced in different batches varies a lot and (2) the spontaneous oxidation needs several years or even decades to occur. Hence, the flavour formation mechanism of Baijiu aging was investigated using electrochemistry and UPLC-Q-Orbitrap-MS/MS, which enabled us to solve the two difficulties above. The oxidation reaction on gold surface could accelerate Baijiu aging by catalyzing the transformation from alcohols to acids. Although natural aging contributed more diverse compound changes to Baijiu, the oxygen-based oxidation process during natural aging was similar to that in the electrochemical oxidation as a whole. This study provides new insights to flavour formation mechanism of aged liquors and provides a new way for liquor-related enterprises to optimise the aging process.

Mechanisms of the regulation of ester balance between oxidation and esterification in aged Baijiu.

The influence of oxidation and esterification on the ester balance of aged Baijiu and methodology for the rational design of liquor flavors to optimize the practice of Baijiu production are not completely understood. We investigated the influence of ester balance on the flavor compounds of aged Baijiu by conducting constituent analysis of Baijiu from different aging times (0, 1, 2, 3, 4, 5, and 10 years). The changes of the main flavor compounds in the aging process were determined, and the correlations among different chemical reactions, such as oxidation, hydrolysis, and esterification, were systematically expounded. Furthermore, cluster analysis of the heat map indicated significant differences between aged Baijiu and new Baijiu and recommended a suitable aging time of 2-3 years.

Influence of Electrochemical Oxidation on the Maturation Process of the Distilled Spirit.

Optimizing the aging process is urgently required in the distilled spirit industry because of the time-consuming and expensive procedure of natural aging. Herein, the componential changes of the liquor sample are confirmed by the component analysis (e.g., gas chromatograph), and the effect of electrochemical oxidization treatment on the overall properties of typical Chinese liquor (Baijiu) is investigated. The key finding is that high oxidative potential can be used to catalyze the oxidation of alcohols, and the reaction rate is dramatically faster than that in the process of natural aging. The present study reveals the influence of electrochemical oxidation on the contents of compounds (particularly, the alcohols) in Baijiu and offers a perspective into the utilization of electrochemical oxidization treatment as an alternative strategy for artificial maturation of Baijiu.

Disinfection of Ready-to-Eat Lettuce Using Polyhexamethylene Guanidine Hydrochloride.

As a novel and safe sanitizer, polyhexamethylene guanidine hydrochloride (PHMG) has been used to inhibit the spoilage of agricultural products caused by fungi. However, little is known about its antibacterial effects on vegetables. In this study, we evaluated the disinfection efficacy of PHMG on ready-to-eat lettuce. PHMG (150-200 mg/L) treatment for 5 min was optimal for lettuce disinfection. Compared to several household sanitizers (vinegar: 1% acetic acid; kettle descaler: 1% citric acid; "84" disinfectant: 200 mg/L sodium hypochlorite), PHMG showed the greatest reductions in Escherichia coli O157:H7, Listeria monocytogenes, aerobic mesophilic counts, aerobic psychrotrophic counts and molds and yeasts. Quality analysis of color (as determined by L*, a* and b*) and determination of electrolyte leakage indicated that PHMG did not cause any additional quality loss as compared to other household sanitizers. These results provide a reference for the application of PHMG as a vegetable sanitizer at the ready-to-eat stage.

Combination of polyhexamethylene guanidine hydrochloride and potassium peroxymonosulfate to disinfect ready-to-eat lettuce.

There is increasing demand for improved fresh produce disinfection technology during the ready-to-eat stage, especially in low-income developing countries. We previously reported that polyhexamethylene guanidine hydrochloride (PHMG) is an effective sanitizer using fresh-cut lettuce as a model. As a low-cost alternative, in the present study, we examined the disinfection efficacy of combining PHMG with the oxidizing sanitizer potassium peroxymonosulfate (PMS). PHMG (150 mg L-1) reduced the counts of Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, Salmonella typhimurium, and naturally present microbes on ready-to-eat lettuce. The disinfection efficacy of PMS was significantly lower than that of PHMG; however, the efficacy of their combination (100 mg L-1 PHMG + 50 mg L-1 PMS, 50 mg L-1 PHMG + 100 mg L-1 PMS, and 50 mg L-1 PHMG + 50 mg L-1 PMS) was equivalent to that of PHMG alone. Color and sensory analyses (crispness, color, flavour, and off-odor) indicated that the combination of PHMG and PMS will not lead to additional quality loss when compared with tap water treatment, and electrolyte leakage analysis showed no additional lettuce surface damage of the combination when compared with PHMG-only treatment. These results show that partial replacement of PHMG by PMS is a cost-reducing strategy, providing a theoretical foundation for its practical application.

Metabolomic Profiling of Carotenoid Constituents in Physalis peruviana During Different Growth Stages by LC-MS/MS Technology.

With the current ongoing changes in global food demands, natural carotenoids are preferred by consumers and are gaining attention among food scientists and producers alike. Metabolomic profiling of carotenoid constituents in Physalis peruviana during distinct on-tree growth stages was performed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology. The results show that the ß rings of ß-carotene are hydroxylated with great efficiency, and there is a continual synthesis of zeaxanthin at half-ripe and full-ripe stages, which is confirmed by relating the zeaxanthin content to that of its precursor (ß-carotene). Lutein was, in terms of mass intensity, the most abundant carotenoid constituent (64.61 µg/g at the half-ripe stage) observed in this study. In addition, γ-carotene, which is rare in dietary fruits and vegetables, was detected in the mature and breaker stages, albeit at a relatively low level. The results suggest that when we consider the variation in carotenoid content during different growth stages, Physalis peruviana can be considered a good source of natural carotenoids.

Similarity studies of DNA sequences based on a new 2D graphical representation.

We denoted the four nucleotides, A, T, G and C, as four two-component vectors, and illustrated a nucleotide sequence as a curve in the 2D space by concatenating the vectors representing the nucleotides in the sequence. We studied the similarities among multiple nucleotide sequences by comparing their corresponding curves, with the beta-globin genes from 7 species as an example.