Biogenic amine content of boza: A traditional cereal-based, fermented Turkish beverage

Boza is a fermented beverage made from millet, maize, wheat or rice. Biogenic amine contents of 10 boza samples from different manufacturers in Turkey were analysed for the first time, using HPLC after derivatisation with benzoyl chloride. Of the 11 biogenic amines under study, putrescine, spermidine and tyramine were detected in all boza samples. Tyramine was the prevailing biogenic amine. Tyramine concentrations of boza samples were between 13 and 65 mg/kg. Total biogenic amine contents of boza samples were between 25 and 69 mg/kg. Consequently, consumption of boza might represent a health risk for patients being treated with drugs containing monoamine oxidase inhibitor (MAOI). The pH values of boza samples were in the range from 3.16 to 4.02; total dry matters were from 15.3% to 31.1% (w/w); protein contents were from 0.50% to 0.99% (w/w). No significant correlations were detected between biogenic amine concentrations and pH, protein content and total dry matter content.     

高直链淀粉消化前后结构变化与抗性淀粉结构剖析

该研究通过不同加热方式获得三种结构不同高直链淀粉,然后进行模拟人体小肠消化实验,分别采用SEM、XRD、SAXS和HPLC等分析手段对其消化前后的分子结构及形态变化进行分析。结果显示三种抗性淀粉(RS)内部结晶区与无定型区交错堆叠的方式不同。三种RS结构共同点是均含有高比例低分子量的直链淀粉及少量高分子量和中等分子量淀粉分子。UV/可见光扫描与切枝酶处理实验揭示了该低分子量直链淀粉具有分枝程度极低结构特征。     

微波-酶法制备马铃薯抗性淀粉工艺参数的优化

以马铃薯精制淀粉为原料,抗性淀粉得率为评价指标,通过单因素及正交试验确定了微波-酶解法制备马铃薯抗性淀粉的最佳工艺条件:在淀粉乳质量分数15%,微波作用时间90 s,微波作用功率800 W,耐高温α-淀粉酶添加量10 CU/g干淀粉,耐高温α-淀粉酶作用时间30 min,普鲁兰酶添加量0.10 PUN(G)/g干淀粉,普鲁兰酶酶解时间6 h,普鲁兰酶作用温度55℃的条件下,4℃老化24 h。经重复验证,RS得率最高达14.0%。     

婴幼儿谷类辅助食品加工工艺对其脱氧雪腐镰刀菌烯醇及衍生物影响

脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)是由镰刀菌在侵染小麦等禾谷类作物过程中产生的一种有毒次级代谢产物,主要污染小麦、大麦、燕麦、黑麦和玉米等谷物。DON在植物和微生物作用下会转化形成各种衍生物,且这些衍生物可与DON原型同时存在,增加了谷物及其相关制品的安全风险。谷类辅食是婴幼儿膳食中的重要组成部分,且婴幼儿对毒素的敏感性更强,应严格限制DON及其衍生物在谷类辅食中被检出。已有研究表明谷物类食品的制作加工方式会对DON及其衍生物的含量水平产生影响,但专门针对婴幼儿消费人群的谷类辅助食品的加工过程如何影响DON及其衍生物水平还鲜有报道。目前婴幼儿谷类辅助食品中DON及其衍生物含量存在超标问题,严重影响婴幼儿这类特殊人群的生长发育和健康。本文从婴幼儿谷类辅食中DON及其衍生物的污染状况及其在加工过程中的含量变化等方面进行较为详细的阐述,以期为婴幼儿谷类辅食中DON的风险评估及防控策略的制定提供有利参考。     

Behavior of Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Shigella flexneri and Shigella sonnei during production of pulque, a traditional Mexican beverage

Pulque is a typical fermented alcoholic beverage of central Mexico, produced from the nectar of maguey agave plants. Production systems are largely artisanal, with inadequate hygiene conditions and exposure to multiple contamination sources. No data exist on pulque microbiological safety and the behavior of pathogenic microorganisms in agave nectar and pulque. An initial trial was done of the behavior of Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Shigella flexneri and Shigella sonnei during fermentation of nectar from a single producer, nectar mixture from different producers, and seed pulque. A second trial simulating artisanal pulque production was done by contaminating fresh nectar with each of the five strains, storing at 22°C for 14 h, adding seed pulque, and fermenting until pulque was formed. During incubation at 16 or 22°C in the first trial, all the pathogenic strains multiplied in both the single producer nectar and the nectar mixture, reaching maximum concentrations at 12 h. Strains concentration then decreased slowly. In the seed pulque, the strains did not multiply and tended to die. In the second trial, all strains increased concentration from 0.7 to 1.6 log at 22°C, and from 0.5 to 1.1 at 16°C in the first 14 h. After addition of seed pulque, they were quickly deactivated until none was detected in the final product. The results suggest that the potential risk to consumers of contracting any of the five tested pathogenic bacterial strains from pulque is low.     

Changes in chemical composition,grain malting,starch and tannin contents and protein digestibility during germination of sorghum cultivars

Malting loss and changes in chemical composition, starch and tannin contents and in vitro protein digestibility (IVPD) were determined during germination of low (0.32%) and high (1.44%) tannin sorghum cultivars. For both cultivars, crude protein, fibre, fat and ash contents were slightly decreased after soaking and germination of the seeds. Malting loss was slightly increased for both cultivars and for all germination periods. Starch degradation was high for both cultivars. Depending on the soaking time about 56–66% and 98–99% tannin were lost during 72 h germination in low and high tannin cultivars, respectively. IVPD was markedly decreased in the low tannin cultivar and markedly increased in the high tannin one with the germination time. Soaking, on the other hand, was found to have a minor effect on IVPD. It is suggested that tannins are responsible for retarding the protein digestibility and starch degradation, especially in the high tannin cultivar.     

Bacterial community succession and metabolite changes during the fermentation of koumiss,a traditional Mongolian fermented beverage

The microbial population in koumiss, a traditional Mongolian fermented beverage, plays a vital role in its nutritional value, beneficial functions, and flavour. We used the Illumina MiSeq platform to investigate the successive bacterial communities produced during koumiss fermentation; dynamic changes in chemical composition of koumiss were also analysed. The correlation between bacterial species and major metabolites was then evaluated. The dominant bacterial species identified during the process of koumiss fermentation were Lactobacillus helveticus, Streptococcus parauberis (phylum Firmicutes), and Acetobacter pasteurianus (phylum Proteobacteria). Lactose content decreased during fermentation, whereas lactic acid, acetic acid, and butyric acid content increased, resulting in decreased pH. The changes in lactose, lactic acid, butyric acid, and pH were mainly correlated with the presence of the bacterial genera Acetobacter, Leuconostoc, Pediococcus, and Bacteroides. Information from these results could advance our understanding of koumiss fermentation, and also help improve the safety, flavour, and therapeutic applications of koumiss.     

甘薯淀粉传统工艺优化

采用极差分析法,对甘薯淀粉生产发酵条件各因素的K、k及R值(极差)的大小进行分析.结果表明,料液比是影响淀粉得率的最主要因素,其次为发酵时间,最后是发酵温度、分离时间.通过单因素试验和L9(34)4因素3水平正交试验,以淀粉得率为标准,确定甘薯淀粉发酵最佳工艺为:料液比1 ∶ 5、分离时间12h、发酵温度为15℃、发酵时间48h.     

Changes in the volatile flavour components of Jinhua ham during the traditional ageing process

Changes in volatile flavour compounds of Jinhua ham were studied during the traditional ageing process of sun‐drying, loft‐ageing and post‐ageing. About seventy‐eight volatile compounds were tentatively identified, including aldehydes (ten to fifteen), carboxylic acids (eight to ten), alcohols (thirteen to fourteen), ketones (eight), esters (eight to ten), aromatic hydrocarbons (five), sulphur‐containing compounds (two to three) and pyrazines (zero to four) which were the main components. The percentage content of aldehydes and ketones reduced over time as the temperature rose with each stage of the process, whereas alcohols, carboxylic acids, esters, pyrazines and sulphur‐containing compounds increased gradually. Jinhua ham's high‐temperature maturating process (40 days at 30–37 °C) made the percentage content of carboxylic acids arising from Maillard reactions markedly increase (from sun‐dried ham 8.45% to fully aged ham 19.23%). This was the most obvious difference between Jinhua ham and the Mediterranean dry‐cured hams, and was the main factor leading to the unique flavour of Jinhua ham.     

Changes in quality and composition of sunflower oil during enzymatic degumming process

The objective of this study was to examine the effect of the enzymatic degumming process on composition of crude sunflower oil.     

Changes in carbohydrates during the production of coffee substitute extracts,especially in the roasting process

The changes in the content of starch, dextrin and reducing sugars in rye and barley, and inulin and fructose in chicory roots, during the roasting process, were investigated. The analysis of carbohydrates was connected with the estimation of changes in extract content, colour of the roasted materials, pH and the sensoric evaluation of the brew. The changes in the content of the respective carbohydrates in the basic stages of the whole process of production of coffee substitute extract were also investigated.In the case of roasted rye and barley the high quality of the brew was connected with the highest content of dextrin and reducing sugars. In the case of roasted chicory the highest fructose content (～13%) and the relation between inulin and fructose may be recognised as parameters for ‘optimum’ quality.As a result of the specific technology of the enzymatic treatment of the extract, a very characteristic carbohydrate composition in the final product, with a high content of dextrins (above 30%) and of reducing sugars, could be observed.     

枸杞黄酒复合饮品的生产工艺研究

以黄酒为主要原料,添加枸杞汁制成枸杞黄酒复合饮品。探讨了加工工艺,并采用正交实验设计,确定枸杞黄酒复合饮品的最佳配方为:黄酒清液28%,枸杞10%,白砂糖8%,阿斯巴甜0.03%,柠檬酸为0.12%,pH4.2~4.5。     

襄阳传统发酵大头菜生产过程中理化特性的变化

以襄阳传统发酵大头菜为研究对象,研究发酵过程中不同阶段大头菜脂肪含量、纤维素含量、蛋白质含量以及色度和质构特性的变化。结果表明,随着发酵的进行,大头菜的脂肪含量无显著变化（P＞0.05）,而纤维含量和蛋白质含量显著降低（P＜0.05）,纤维素含量从3.33%降至1.00%,蛋白质含量从2.02%降至0.70%。大头菜内部由白色逐渐变为深褐色,L*值逐渐降低;a*值和b*值呈现先增大后减小的趋势,ΔE值逐渐增大,各加工阶段的大头菜整体色泽差异显著（P＜0.05）。大头菜的硬度、脆性较新鲜时显著提高（P＜0.05）,而咀嚼性显著降低（P＜0.05）。该研究可为今后传统发酵大头菜的工业化、标准化生产提供一定的参考价值。     

Analysis of bacterial community during the fermentation of pulque, a traditional Mexican alcoholic beverage, using a polyphasic approach

In this study, the characterization of the bacterial community present during the fermentation of pulque, a traditional Mexican alcoholic beverage from maguey (Agave), was determined for the first time by a polyphasic approach in which both culture and non-culture dependent methods were utilized. The work included the isolation of lactic acid bacteria (LAB), aerobic mesophiles, and 16S rDNA clone libraries from total DNA extracted from the maguey sap (aguamiel) used as substrate, after inoculation with a sample of previously produced pulque and followed by 6-h fermentation. Microbiological diversity results were correlated with fermentation process parameters such as sucrose, glucose, fructose and fermentation product concentrations. In addition, medium rheological behavior analysis and scanning electron microscopy in aguamiel and during pulque fermentation were also performed. Our results showed that both culture and non-culture dependent approaches allowed the detection of several new and previously reported species within the alpha-, gamma-Proteobacteria and Firmicutes. Bacteria diversity in aguamiel was composed by the heterofermentative Leuconostoc citreum, L. mesenteroides, L. kimchi, the gamma-Proteobacteria Erwinia rhapontici, Enterobacter spp. and Acinetobacter radioresistens. Inoculation with previously fermented pulque incorporated to the system microbiota, homofermentative lactobacilli related to Lactobacillus acidophilus, several alpha-Proteobacteria such as Zymomonas mobilis and Acetobacter malorum, other gamma-Proteobacteria and an important amount of yeasts, creating a starting metabolic diversity composed by homofermentative and heterofermentative LAB, acetic and ethanol producing microorganisms. At the end of the fermentation process, the bacterial diversity was mainly composed by the homofermentative Lactobacillus acidophilus, the heterofermentative L. mesenteroides, Lactococcus lactis subsp. lactis and the alpha-Proteobacteria A. malorum. After a 6-h fermentation, 83.27% of total sugars detected after inoculation were consumed (228.4 mM hexose equivalents) and a carbon (C) recovery of 66.18% in fermentation products was estimated. They were produced 284.4 mM C as ethanol, 71.5 mM C as acetic acid and 19 mM C as lactic acid, demonstrating the presence of homo- and heterofermentative, acetic and alcoholic metabolisms in the final product. It was also found, after hydrolysis, that the exopolysaccharide produced during the fermentation was mainly composed by fructose residues, probably inulin or levan.     

新旧工艺黄酒发酵过程中主要高级醇的变化研究

文章用气相色谱法对新工艺及传统工艺黄酒发酵过程中的主要高级醇——正丙醇、异丁醇、异戊醇、β-苯乙醇进行了跟踪测定,结果表明,2种工艺黄酒在发酵过程中总高级醇含量一直处于上升状态,前发酵阶段上升速率要明显高于后发酵.新工艺条件下黄酒中82％的高级醇在前发酵阶段形成,传统工艺下这个比例为73％,发酵结束时新工艺黄酒总高级醇含量比传统工艺黄酒高56.60mg/L.发酵过程中高级醇组分间的比例——正丙醇∶异丁醇∶异戊醇∶苯乙醇近似为1∶2∶5∶1,这个比值在整个发酵过程中变化不大,且与新旧工艺路线无关.     

硒化绿豆抗性淀粉制备工艺优化及抗氧化活性分析

本文以绿豆抗性淀粉(Mung bean resistant starch,MB-RS4)为原料,通过单因素结合响应面优化得到硒化绿豆抗性淀粉(Selenized mung bean resistant starch,MB-RS4?Se(IV))最佳制备工艺：在反应时间3.5 h,反应温度66℃,硝酸浓度0.5%,料液比1:1时得到MB-RS4?Se(IV)硒含量2.21 mg/g,得率26.4506%;采用光学显微镜、偏光十字显微镜、扫描电镜观察硒化前后光学性质发现淀粉颗粒先聚集成团后破碎变小,偏光十字发生散射后逐渐消失;体外测定硒化前后抗氧化活性并进行相关性分析,硒化后对.OH、.O_^2-、ABTS_⁺抑制作用及总还原能力增强,并与浓度表现出较大相关性。