Efficient and selective upcycling of waste polylactic acid into acetate using nickel selenide

The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products.

Constructing a stable interface on Ni-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode via lactic acid-assisted engineering strategy

Ni-rich layered oxides are potential cathode materials for next-generation high energy density Li-ion batteries due to their high capacity and low cost.However,the inherently unstable surface properties,including high levels of residual Li compounds,dissolution of transition metal cations,and parasitic side reactions,have not been effectively addressed,leading to significant degradation in their electrochemical performance.In this study,we propose a simple and effective lactic acid-assisted interface engineering strategy to regulate the surface chemistry and properties of Ni-rich LiNi_(0.8)Co_(0.1)Mr_(0.1)O_(2) cathode.This novel surface treatment method successfully eliminates surface residual Li compounds,inhibits structural collapse,and mitigates cathode-electrolyte interface film growth.As a result,the lactic acidtreated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) achieved a remarkable capacity retention of 91.7% after 100 cycles at 0.5 C(25℃) and outstanding rate capability of 149.5 mA h g^(-1) at 10 C,significantly outperforming the pristine material.Furthermore,a pouch-type full cell incorporating the modified LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode demonstrates impressive long-term cycle life,retaining 81.5% of its capacity after 500 cycles at 1 C.More importantly,the thermal stability of the modified cathode is also dramatically improved.This study offers a valuable surface modification strategy for enhancing the overall performance of Ni-rich cathode materials.

Application of Next Generation Sequencing for Rapid Identification of Lactic Acid Bacteria

The rapid identification of lactic acid bacteria,which are essential microorganisms in the food industry,is of great significance for industrial applications.The identification of lactic acid bacteria traditionally relies on the isolation and identification of pure colonies.While this method is well-established and widely used,it is not without limitations.The subjective judgment inherent in the isolation and purification process introduces potential for error,and the incomplete nature of the isolation process can result in the loss of valuable information.The advent of next generation sequencing has provided a novel approach to the rapid identification of lactic acid bacteria.This technology offers several advantages,including rapidity,accuracy,high throughput,and low cost.Next generation sequencing represents a significant advancement in the field of DNA sequencing.Its ability to rapidly and accurately identify lactic acid bacteria strains in samples with insufficient information or in the presence of multiple lactic acid bacteria sets it apart as a valuable tool.The application of this technology not only circumvents the potential errors inherent in the traditional method but also provides a robust foundation for the expeditious identification of lactic acid bacteria strains and the authentication of bacterial powder in industrial applications.This paper commences with an overview of traditional and molecular biology methods for the identification of lactic acid bacteria.While each method has its own advantages,they are not without limitations in practical application.Subsequently,the paper provides an introduction of the principle,process,advantages,and disadvantages of next generation sequencing,and also details its application in strain identification and rapid identification of lactic acid bacteria.The objective of this study is to provide a comprehensive and reliable basis for the rapid identification of industrial lactic acid bacteria strains and the authenticity identification of bacterial powder.

Screening of glucosinolates degrading lactic acid bacteria and their utilization in rapeseed meal fermentation

Rapeseed meal is a promising food ingredient, but its utilization is limited by the presence of some potentially harmful ingredients, such as glucosinolates. Fermentation is a cost-effective method of detoxication but a food-grade starter culture with glucosinolates degradation capacity is required. In this study, 46 strains of lactic acid bacteria from traditional paocai brines were screened for their ability to glucosinolate degradation. The results showed that more than 50% of the strains significantly degraded glucosinolates. Two strains of Lactiplantibacillus(p7 and s7) with high capacity of glucosinolates degradation through producing enzymes were identified. Then,an optimized condition for rapeseed meal fermentation by p7 was established to degrade glucosinolates, which can achieve about 80% degradation. UPLC/Q-TOF-MS analysis showed that the degradation rate of individual glucosinolates was different and the degradation rate of gluconapin and progoitrin in rapeseed meal can reach more than 90%. Meanwhile, fermentation with p7 can improve safety of rapeseed meal by inhibiting the growth of Enterobacteriaceae and improve its nutritional properties by degrading phytic acid. The in vitro digestion experiments showed that the content of glucosinolates in rapeseed meal decreased significantly during gastric digestion. Meanwhile, fermentation with p7 can greatly improve the release of soluble protein and increase the contents of free essential amino acids, such as lysine(increased by 12 folds) and methionine(increased by 10 folds).

Allergen degradation of bee pollen by lactic acid bacteria fermentation and its alleviatory effects on allergic reactions in BALB/c mice

Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.

Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging

The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA via the solvent casting technique,the water vapor barrier property of the PLA/OC/ZnOfilm improved by a maximum of 86%compared to the neat PLAfilm without the deterioration of Young’s modulus or the tensile strength.Moreover,thefilm’s self-antibacterial activity against foodborne pathogens,including gram-negative(Escherichia coli,E.coli)and gram-positive(Staphylococcus aureus,S.aureus)bacteria,was enhanced by a max-imum of approximately 98–99%compared to the neat PLAfilm.Furthermore,SEM images revealed the homo-geneous dispersion of both nano-fillers in the PLA matrix.However,the thermal stability of thefilm decreased slightly after the addition of the OC and ZnO.Thefilm exhibited notable light barrier properties in the UV-Vis range.Moreover,the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced theflexibility of the nanocompositefilm by increasing the elongation at break approxi-mately 1.5-fold compared to that of the neat PLAfilm.This contributes to its feasibility as an active food packa-ging material.

Biguanides and lactic acidosis:unraveling the complex relationship

Biguanides,such as metformin,have long been established as frontline medications for the management of type 2 diabetes due to their glucose-lowering effects and favorable safety profiles.However,concerns regarding the risk of lactic acidosis associated with biguanide use have sparked considerable debate and scrutiny.This research article aims to provide a comprehensive analysis of the relationship between biguanides,particularly metformin,and lactic acidosis.We delve into the underlying mechanisms,epidemiological evidence,risk factors,clinical manifestations,diagnostic considerations,and management strategies related to biguanide-induced lactic acidosis.Additionally,we explore recent research developments,controversies,and future directions in this critical area of pharmacovigilance and clinical practice.

Poly(lactic acid)-aspirin microspheres prepared via the traditional and improved solvent evaporation methods and its application performances

Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, therefore a controllable delivery of aspirin is of importance to lighten those side effects. In this work, poly(lactic acid)(PLA) was chosen as the carrier to prepare PLA-aspirin microspheres by using the traditional and the improved solvent evaporation methods. It was found that no matter which experimental condition was, the encapsulation efficiency of aspirin was higher by using the improved method than that of the traditional method. Specifically, when the concentration of polyvinyl alcohol = 1%(mass),the polymer concentration = 1:20, the oil/water rate = 1:2.5, PLA-aspirin microspheres were obtained via the improved method with a high yield of 82.83%(mass) and an encapsulation efficiency of 44.09%. PLAaspirin microspheres were then prepared continuously using the improved method, which further enhanced the encapsulation efficiency to 54.56%. Approximate 85% aspirin released from microspheres within 7 days. Obvious degradation which was represented by reduction on hardness was observed by soaking microspheres in PBS for 60 days. This work is of interest because it provides a continuous route to prepare PLA-aspirin microspheres continuously with a high drug encapsulation efficiency.

3D printed lactic acid bacteria hydrogel:cell release kinetics and stability

In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded with LAB can be freeze-dried and reused for more than 100 times.The bio-hydrogel can be used to co-culture different LAB and keep its fermentation performance stable in long-term use.The release kinetics model and response surface method were used to simulate and optimize the bacteria release mode in the bio-hydrogel.The results show that the release of bacteria from hydrogel is regulated by the coupling of Fickian diffusion and polymer swelling.The stability of LAB hydrogel was evaluated by reuse experiments.The images of confocal microscopy and scanning electron microscope showed that the bacteria with high cell viability were distributed in the hydrogel and intact structure of the living hydrogel was maintained after 100 times of reuse as yoghurt starter.In conclusion,the 3 D printed LAB bio-hydrogel developed in this study has the advantage of reuse and sustainability,which is expected to open up a new way for the preparation of food culture starter.

Potential Probiotic Tiger Nut-Cashew Nut-Milk Production by Fermentation with Two Lactic Bacteria Isolated from Ivorian Staple Foods

Probiotification of plant milk can improve its sensory and health-promoting properties. As traditional fermented foods where lactic acid bacteria (LAB) are present have been associated with beneficial effects on human health, the beneficial effects of two LAB recently isolated from two current Ivorian staple foods (a pepper and a traditional beer) were screened. These two strains LAC 1 (Lactobacillus plantarum) and LAC 2 (Pediococcus acidilactici) which presented probiotic, exopolysaccharides, inflammatory and anti-oxidant activities, were used to ferment a composite plant milk of tiger-nut and cashew (80/20) compared to two starters of a commercial yogourt. The obtained plant milks SCT 2 and SCT 3 with a significant increase in their antioxidant and/or anti-inflammatory activities and lactic bacteria contents were more preferred by consumers than SCT 1 obtained by fermentation of the commercial yogourt starters. The mixing of LAC 1 and LAC 2 was not beneficial. SCT 2 (with an anti-inflammatory activity of 31.38% and an anti-oxidant activity of 17.30%) and SCT 3 (with an anti-oxidant activity of 22.28) could be further tested in animal models to verify their nutrition-health claims.

Hydrothermal conversion of fructose to lactic acid and derivatives:Synergies of metal and acid/base catalysts

With increasing strict regulation on single-use plastics,lactic acid(LA)and alkyl lactates,as essential monomers for bio-degradable polylactic acid(PLA)plastic products,have gained worldwide attention in both academia and industry.While LA is still dominantly produced through fermentation processes from start,chemical synthesis from cellulosic biomass remains a grand challenge,owing to poor selectivity in activating CAH and CAC bonds in sugar molecules.To our best knowledge,recent publications have been focused on hydrothermal conversion of glucose to LA,while this review summarizes the highlights on direct thermal conversion of fructose as starting material to LA and derivatives.In particular,the synergies of metal/metal cations and acid/base catalysts will be critically revised on retro-aldol and dehydration reactions.This work will provide insights into rational design of active and selective catalysts for the production of carboxylic acids from biomass feedstocks.

Diarrhea and Acute Renal Injury Culminating in Metformin-Induced Lactic Acidosis

Background: Metformin (M) is an effective first-line hypoglycemic agent in obese type 2 diabetes mellitus due to its low cost and safety profile. The Case: A 66-year-man presented with shock due to lactic acidosis induced by M-supersaturation subsequent to acute renal failure following infective diarrhea. The drug has been used, by this patient, for >10 years without complication. Physical examination, laboratory tests, radiological investigations and blood cultures did not show evidence of new cardiac, hepatic and septic insult. Despite discontinuation of M and 2-days of aggressive hydration, bicarbonate infusions and pressors;toxic levels of the drug persisted and shock-state culminated in severe and oliguric renal failure with serum urea and creatinine up to 50 mmol/L and 1270 umol/L, respectively. Hence, continuous venovenous hemodiafiltration (CVVHDF) was used, for 16-hours, to remove the drug, correct his acidosis and support his severe renal complications. Hours after the procedure;drug level, lactic acidosis and its associated shock improved followed by gradual renal recovery. The patient was discharged after 6 days and serum creatinine reached his base line (180 umol/L) 2 weeks later. The drug was not recommended for his future use. Conclusion: M-induced lactic acidosis, should be considered in assessment of shock in M-treated patients and management of unstable patients indicates early-use of CVVHDF.

Effects of lactic acid bacteria-fermented formula milk supplementation on ileal microbiota,transcriptomic profile,and mucosal immunity in weaned piglets

Background:Lactic acid bacteria(LAB)participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites,which has numerous roles in the intestinal health-promot-ing of the consumer.However,information is lacking regarding the application prospect of LAB fermented milk in the animal industry.This study investigated the effects of lactic acid bacteria-fermented formula milk(LFM)on the growth performance,intestinal immunity,microbiota composition,and transcriptomic responses in weaned piglets.A total of 24 male weaned piglets were randomly divided into the control(CON)and LFM groups.Each group consisted of 6 replicates(cages)with 2 piglets per cage.Each piglet in the LFM group were supplemented with 80 mL LFM three times a day,while the CON group was treated with the same amount of drinking water.Results:LFM significantly increased the average daily gain of piglets over the entire 14 d(P<0.01)and the average daily feed intake from 7 to 14 d(P<0.05).Compared to the CON group,ileal goblet cell count,villus-crypt ratio,sIgA,and lactate concentrations in the LFM group were significantly increased(P<0.05).Transcriptomic analysis of ileal mucosa identified 487 differentially expressed genes(DEGs)between two groups.Especially,DEGs involved in the intestinal immune network for IgA production pathways,such as polymeric immunoglobulin receptor(PIGR),were significantly up-regulated(P<0.01)by LFM supplementation.Moreover,trefoil factor 2(TFF2)in the LFM group,one of the DEGs involved in the secretory function of goblet cells,was also significantly up-regulated(P<0.01).Sequenc-ing of the 16S rRNA gene of microbiota demonstrated that LFM led to selective enrichment of lactate-producing and short-chain fatty acid(SCFA)-producing bacteria in the ileum,such as an increase in the relative abundance of Entero-coccus(P=0.09)and Acetitomaculum(P<0.05).Conclusions:LFM can improve intestinal health and immune tolerance,thus enhancing the growth performance of weaned piglets.The changes in microbiota and metabolites induced by LFM might mediate the regulation of the secretory function of goblet cells.

传统发酵乳品中产广谱细菌素乳酸菌选育

为选育产广谱细菌素乳酸菌,采用琼脂扩散法对甘肃牧区传统发酵乳品中分离纯化的96株乳酸菌进行了筛选,并确定产细菌素菌株,具有最佳抑菌效果的菌株经重离子束12C6+辐照诱变,再采用培养皿分区法进行6种指示菌广谱抑菌性能比较。结果表明,琼脂扩散法筛选出抑菌效果最佳的产细菌素菌株Lp1,经辐照诱变得到98株突变菌,选育出对大肠埃希氏菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、单核细胞增生李斯特氏菌(Listeria monocytogenes)、沙门氏菌(Salmonella)、志贺氏菌(Shigella)和克罗诺杆菌(Cronobacter)抑菌性能均明显优于出发菌株Lp1的5株突变株L088、L087、L063、L049、L010进行广谱抑菌试验,其中菌株L088和L063为广谱抑菌性能较好菌株,突变株L088对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高47.81%、33.28%、22.97%、45.25%、21.39%、40.21%,突变株L063对上述6种指示菌的抑菌扇环半径比出发菌株Lp1抑菌扇环半径分别提高54.27%、29.18%、25.37%、58.03%、17.85%、42.13%。采用培养皿分区法可同时在1个培养皿中完成检测6种指示菌的抑菌试验,可高效筛选产广谱细菌素乳酸菌。

林麝肠道中乳酸菌的分离筛选及益生特性

本研究旨在从健康林麝粪便中分离筛选用于改善林麝健康状况的潜在益生菌株,并对其进行体外益生性评价。共分离获得12株乳酸菌,结合细胞个体形态观察及细菌16S rDNA序列鉴定,体外评价其耐酸和耐胆盐能力,测定其对5种目标病原菌(大肠埃希氏菌Escherichia coli ATCC 25922、金黄色葡萄球菌Staphylococcus aureus ATCC 25923、铜绿假单胞菌Pseudomonas aeruginosaPAO1、肠炎沙门氏菌Salmonella enteritidisATCC 13076和化脓隐秘杆菌Arcanobacterium pyogenes LSN3)的拮抗活性、自聚集和疏水性、抗生素敏感性、抗药性基因型和生长曲线。结果显示,5株植物乳植杆菌(Lactiplantibacillus plantarum)和1株乳酸片球菌(Pediococcus acidilactici)在pH 4酸性条件或质量分数0.5%胆盐环境中,存活率分别达88.5%和87%以上;能够抑制前4种目标病原菌(抑菌圈直径17.20~20.19 mm)和化脓隐秘杆菌LSN3(抑菌圈直径14.23~15.53 mm);与对照菌株副干酪乳酪杆菌(L. paracasei)L22具有相近的自聚集(53.1%~56.2%)和表面疏水率(52.9%~56.0%);对链霉素、环丙沙星和万古霉素耐药;携带万古霉素抗性基因vanX;具有快速生长的特点(培养24 h后OD600分别达9.0和7.1左右)。本研究筛选出的6株乳酸菌可作为后续开发林麝用益生菌制剂的一种可靠的菌株来源。

益生菌基因组学在乳酸菌筛选和功能评价中的应用

乳杆菌和双歧杆菌是益生菌筛选的主要微生物类群,在促进人类、动物甚至植物健康方面都有重要的应用价值,被广泛应用于多种功能性食品、动物饲料和微生物菌肥。然而,这些细菌对宿主健康产生积极影响的分子机制还远未完全了解。另外,传统的益生菌筛选技术主要依靠表型和生理生化特性的测定以及随机对照试验,这些方法不仅耗时、费力,而且数据难以重复。不同研究小组之间数据难以共享,不能实现菌株有益特性的均一性和标准化验证,严重制约了益生菌科学研究的发展和菌株的产业化开发利用。基于新的测序技术和强大的计算机分析方法,被称为益生菌基因组学新学科的出现,允许研究者在短时间内通过筛选大量的生物学和基因组数据,显著提高益生菌筛选的效率和准确性。本文综述了通过基因组数据的分析,帮助人们高效、快速地确定益生菌,开辟益生菌新功能的评价途径。总结益生菌基因组学在阐明益生特性功效评价的分子基础等方面的最新研究成果,以期为扩展研究人员对这些有益微生物生物学的认知,揭示益生菌促进健康特性的分子机制提供新视角。

脓毒症患者连续性血液净化治疗前后PCT Trx-1D-Lac表达及意义

目的:探讨脓毒症患者连续性血液净化(CBP)治疗前后血清降钙素原(PCT)、硫氧还蛋白-1(Trx-1)、D-乳酸(D-Lac)水平变化,分析其对CBP疗效的预测价值及临床意义。方法:选取2021年1月至2022年12月本院100例脓毒症患者作为观察组,另遵循1∶1配对原则,选取100例健康体检者作为对照组。统计两组血清PCT、Trx-1、D-Lac水平。观察组接受CBP治疗,依据治疗效果分为存活亚组、死亡亚组。比较不同亚组血清PCT、Trx-1、D-Lac水平、急性生理学与慢性健康状况Ⅱ评分(APACHEⅡ)及治疗前后其变化差值。Pearson分析各血清指标水平变化差值与APACHEⅡ评分相关性。采用受试者工作特征曲线(ROC)及曲线下面积(AUC)分析各血清指标水平变化差值对疗效的预测价值。采用卡普兰-迈耶(Kaplan-Meier)分析不同血清表达者28d内生存状况。结果:观察组血清PCT、Trx-1、D-Lac水平高于对照组(P<0.05);治疗1周后,死亡亚组血清PCT、Trx-1、D-Lac水平及APACHEⅡ评分高于存活亚组,且变化差值小于存活亚组(P<0.05);各血清指标水平变化差值与APACHEⅡ评分呈正相关(P<0.05);各血清指标水平变化差值联合预测CBP疗效的AUC分别大于单一指标预测、各血清指标联合预测(P<0.05);PCT、Trx-1、D-Lac水平变化差值高表达者死亡风险分别是低表达的4.828、3.600、2.318倍,且生存率高于低表达者(P<0.05)。结论:脓毒症患者CBP治疗前后血清PCT、Trx-1、D-Lac水平变化可反映病情严重程度,且与28d内生存情况密切相关,联合检测其变化差值对CBP疗效具有一定预测价值。

高产乳酸耐热克鲁维酵母的筛选及其在葡萄酒中增酸潜力研究

通过比较16株耐热克鲁维酵母(Lachancea thermotolerans)的产乳酸能力及耐受性,筛选高产乳酸的优良菌株,并将其与商业酿酒酵母(Saccharomyces cerevisiae)EC1118按1∶1配比共发酵制备霞多丽葡萄酒,评估其酿造特性。结果表明,耐热克鲁维酵母菌株LT-XJ24、LT-XJ59、LT-ZX03与LT-GS27的耐受性较好,且产乳酸能力较强,在葡萄汁中的乳酸产量分别为6.41 g/L、6.52 g/L、7.89 g/L和6.21 g/L。优选的4株耐热克鲁维酵母与商业酿酒酵母共发酵均能完成霞多丽葡萄酒的酒精发酵,且均具有良好的生物增酸能力,其中菌株LT-ZX03混合发酵的霞多丽葡萄酒中的乳酸产量最高,达6.66 g/L。尽管混合发酵组提高了葡萄酒的挥发酸含量,但仍然符合相关标准要求(≤1.2 g/L)。从霞多丽葡萄酒样品中共检出41种香气物质,包括23种酯类、11种醇类、5种酸类以及2种其他类化合物,其中13种物质的香气活度值(OAV)>1。不同耐热克鲁维酵母对霞多丽葡萄酒中挥发性香气物质的影响存在差异,其中菌株LT-GS27和LT-ZX03影响较大,能够提高葡萄酒中具有花果香气的丁酸乙酯、己酸乙酯、辛酸乙酯和癸酸乙酯等物质含量。

响应面法优化南瓜风味发酵乳酸菌饮料的研制

为了研制出一款风味独特兼具营养的南瓜风味发酵酸乳饮料,本研究以自制南瓜发酵酸乳为原料,通过单因素实验和响应面试验设计,以感官评分为评价指标,确定了南瓜风味发酵乳酸菌饮料的最佳配方为:水料和酸奶体积比为4,柠檬酸添加量0.12%,糖添加量为8%。以《食品安全国家标准食品酸度的测定》(GB5009.239—2016)以及《含乳饮料》(GB/T21732—2008)为标准,测定南瓜风味发酵乳酸菌饮料的酸度为45°T,乳蛋白含量为0.71g/100g,乳酸菌活菌数为2.8×10^(6)CFU/g。以上所述,均符合国家标准。该南瓜风味发酵乳酸菌饮料口感较好,味道醇厚,有较多的乳酸菌含量,具有较好的市场开发前景。