Anthocyanin composition of the red wine Babić affected by maceration treatment

Identification of anthocyanins in the wine made of the Croatian autochthonous grape variety of Babić (Vitis vinifera L.) was carried out and their profile was determined by means of high-performance liquid chromatography with diode array and mass spectrometric detection. Dependence of anthocyanins content and profile on maceration treatment conditions was investigated. Statistically significant differences of anthocyanins concentration in wines Babić produced by various maceration treatments were confirmed by the use of multivariate analysis of variances. The investigation results indicated that the maceration temperature exerts higher influence on anthocyanins concentration than the duration of maceration. In addition, on the basis of anthocyanin composition and using different multivariate statistical analyses, differentiation of wines Babić according to maceration treatments was procured.     

Effect of a pulsed electric field treatment on the anthocyanins composition and other quality parameters of Cabernet Sauvignon freshly fermented model wines obtained after different maceration times

The influence of the application of a pulsed electric field (PEF) treatment (5 kV/cm, 2.1 kJ/kg) to the grape pomace on different quality parameters and anthocyanins content of Cabernet Sauvignon wines obtained after different maceration times (48, 72, 96 and 248 h) has been investigated.Regardless of the maceration time, the application of a PEF treatment led to freshly fermented model wines that were richer in colour intensity, total polyphenols index (TPI), tannins and showed better visual characteristics. It was observed that the concentration of anthocyanins compounds in the freshly fermented model wines obtained from PEF-treated pomace was higher, as compared to the control wine. The HPLC anthocyanic profiles of freshly fermented model wines obtained from PEF-treated pomace were similar to those of control wine indicating that the permeabilization of the cell membranes of pomace did not produce a selective effect on any anthocyanin. Malvidin-3-glucoside and Malvidin-3-glucoside acetate were the predominant anthocyanins in both control and PEF wine.According to the results obtained in this investigation the application of a PEF treatment permitted to reduce the maceration time during vinification of Cabernet Sauvignon grapes from 268 to 72 h.     

Influence of alcoholic fermentation process on antioxidant activity and phenolic levels from mulberries (Morus nigra L.)

The aim of the present study was to evaluate the profile of the phenolic constituents of Morus nigra fruits and their antioxidant activity (DPPH) and to compare their contents before and after fermentation. Antioxidant phenolics of black mulberry (M. nigra L.) samples grown in Galicia (NW Spain) were extracted with methanol/formic acid/water (MFW) and determined by high performance liquid chromatography (HPLC). Two major anthocyanins (cyanidin 3-glucoside and cyanidin 3-rutinoside) and two flavonols (quercetin 3-glucoside and rutin) were isolated, together with caffeic acid and other hydroxycinnamic and ellagic acid derivatives. Their chemical structures were identified by spectral analyses with diode array detection (DAD), but also with alkaline saponification and acid hydrolysis of the mulberry phenolics. Good correlations (r² = 0.6229) were observed among total flavonols contents and the IC₅₀ radical scavenging capacities of mulberry fruits. Anthocyanins are the major flavonoids present in mulberry. It would be expected that anthocyanins contribute significantly to their antioxidant activity; nevertheless, alcohol generated during fermentation may also contribute to antioxidant activity. Our results provide useful antioxidant nutritional information of fresh and fermented mulberry fruits.     

不同果酒酵母发酵血橙果酒的发酵规律及香气成分的比较

以血橙为原料,比较了两种酵母的发酵规律和发酵的血橙果酒的香气成分,并建立两种酵母的发酵动力模型。结果表明:果酒干酵母起酵时间比果酒酵母1383短;发酵过程中残糖及花色苷逐渐降低,酸度呈先上升后下降的趋势;果酒干酵母及果酒酵母1383酿造的血橙果酒中分别检测出36、39种香气成分,其中相同的香气成分有26种;果酒干酵母和果酒酵母1383的酒精发酵动力方程分别为X=9.3511+26.322e-0.993t和X=9.7201+41.109e-0.093t。      

Stability of polyphenols in chokeberry (Aronia melanocarpa) subjected to in vitro gastric and pancreatic digestion

Berries and red fruits are dietary sources of polyphenols with reported health benefits. As part of the diet, polyphenols are ingested as complex mixtures immersed in a food matrix which is digested in the gut. Epithelial cells lining the gut are regularly exposed to these digested mixtures. To understand the effects of dietary polyphenols on human gut health it is essential to determine their stability and fate in the lumen. In this work, we investigated the effects of an in vitro gastric and pancreatic digestion on the stability and composition of the major polyphenols in chokeberry juice. Digestion was carried out with a mixture of pepsin-HCl for 2 h, followed by a 2 h incubation with pancreatin and bile salts at 37 °C with shaking, in the absence of light and under N₂. After digestion, the chokeberry samples were acidified, filtered and HPLC-DAD/HPLC–MS–MS analysed to determine the content of total soluble recovered phenolics. Gastric digestion had no substantial effect on any of the major phenolic compounds in chokeberry, namely anthocyanins, flavan-3-ols, flavonols and caffeic acid derivatives. However, these compounds were significantly altered during the pancreatic digestion and this effect was more marked for anthocyanins (approximately 43% was lost during the 2 h treatment with pancreatin). Flavonols and flavan-3-ols decreased by 26% and 19%, respectively. Neochlorogenic acid decreased by 28% whereas chlorogenic acid was increased by 24%. In vitro digestion of standard phenolic compounds, representing each of the groups of phenolics in chokeberry, confirmed some of the observed changes. Interactions with the digestive enzymes were not responsible for the observed losses which were mostly due to the chemical conditions during pancreatic digestion. Our results, in accordance with previously published results, show that dietary polyphenols are highly sensitive to the mild alkaline conditions in the small intestine and that a good proportion of these compounds can be transformed into other unknown and/or undetected structural forms with different chemical properties and, consequently, different bioaccessibility, bioavailability and biological activity.     

常温低温发酵对二次发酵辣椒酱品质的影响比较

目的 比较分析常温低温发酵对二次发酵辣椒酱品质的影响。方法 本研究测定了不同温度下二次发酵辣椒酱的总酸、氨基酸态氮、总糖、还原糖等指标,采用电子鼻技术对其风味轮廓进行了描述,并通过顶空固相微萃取-气相色谱-质谱法(headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)结合香气活度值对3个发酵时间节点的挥发性成分及主要风味物质进行了分析。结果 辣椒酱的总糖及还原糖含量随发酵时间呈下降趋势,且发酵温度越高,减少的速率越快;总酸含量随发酵时间呈上升趋势,但氨基酸态氮含量变化并不明显;不同温度下发酵辣椒酱风味成分种类存在一定的差异;通过HS-SPME-GC-MS共检出71种挥发性成分。其中乙烯基愈疮木酚(辛香、木香)、苯乙醛(风信子香)、水杨酸甲酯(甜香、薄荷香)、棕榈酸乙酯(奶油香)为不同发酵温度共有的呈香物质。二烯丙基二硫(蒜香)为低温发酵辣椒酱特有的呈香物质,芳樟醇(花香)、肉豆蔻酸甲酯(焦香风味)、油酸乙酯(奶油香)、γ-雪松烯(松木香)等为协调呈香物质。亚油酸乙酯(花果香)、癸酸乙酯(椰子香)、水杨酸甲酯(甜香、薄荷香)、棕榈酸乙酯(奶油香)、4-乙基苯酚(烟熏香)等为常温发酵辣椒酱的呈香物质。结论 常温发酵条件下风味物质的生成速度与增量远优于低温发酵,表明常温发酵优于低温发酵。本研究为盐胚辣椒的风味强化提供了新的思路,为今后辣椒酱及剁辣椒产品开发提供了技术支撑。     

Phenolic characterisation of red grapes autochthonous to Andalusia

Twenty six phenolic compounds in wine grapes were identified and quantified in five winegrape varieties using the complementary information from high-performance liquid chromatography coupled to diode array and fluorescence detectors, and mass spectrometry in both positive and negative mode. Fourteen different anthocyanins were identified in these grapes. In all varieties, malvidin-3-glucoside and its derivatives, mainly p-coumaroyl derivatives, were the major compounds. Seven flavonols were detected, most as quercetin and myricetin derivatives, and few qualitative differences were found among varieties. Total hydroxycinnamic content was rather low in all varieties. Lastly, catechin and epicatechin were detected in both skin and seed; differences in respect of the content in the seeds can be attributed to differences in the number and weight of seed per berry in each variety. The results of the characterisation can be used to select winemaking techniques aimed at improving the quality of the final wine.     

Evaluation of different Saccharomyces cerevisiae strains for red winemaking. Influence on the anthocyanin,pyranoanthocyanin and non-anthocyanin phenolic content and colour characteristics of wines

The possible industrial use of three previously-selected Saccharomyces cerevisiae strains (1EV, 2EV and 7EV) has been studied in musts derived from Tempranillo and Cabernet Sauvignon. The anthocyanin, pyranoanthocyanin and non-anthocyanin phenolic content, and colour characteristics of the resulting wines have been compared to those of a commercial strain. Anthocyanins were the compounds most influenced by the yeast strain. Independently of the grape variety, wines derived from 2EV presented significantly higher anthocyanin concentrations than those derived from 1EV and 7EV, which presented similar contents. With the exception of hydroxycinnamic acids and derivatives, no particular influence of the yeast strain was observed on the remaining non-anthocyanin phenolic compounds (i.e, hydroxybenzoic acids and flavanols). Pyranoanthocyanins and metabolites resulting from the alcoholic fermentation such as tyrosol and tryptophol, seemed to be more influenced by the must composition and pH, and thus, by the grape variety, than by the yeast strain.     

Physical properties of acid milk gels prepared at 37°C up to gelation but at different incubation temperatures for the remainder of fermentation

We investigated the effect of altering temperature immediately after gels were formed at 37°C. We defined instrumentally measurable gelation (IMG) as the point at which gels had a storage modulus (G′) ≥5 Pa. Gels were made at constant incubation temperature (IT) of 37°C up to IMG, and then cooled to 30 or 33.5, or heated to 40.5 or 44°C, at a rate of 1°C/min and maintained at those temperatures until pH 4.6. Control gel was made at 37°C (i.e., no temperature change during gelation/gel development). Gel formation was monitored using small strain dynamic oscillatory rheology, and the resulting structure and physical properties at pH 4.6 were studied by fluorescence microscopy, large deformation rheology, whey separation (WS), and permeability (B). A single strain of Streptococcus thermophilus was used to avoid variations in the ratios of strains that could have resulted from changes in temperature during fermentation. Total time required to reach pH 4.6 was similar for samples made at constant IT of 37°C or by cooling after IMG from 37 to either 30 or 33.5°C, but gels heated to 40 or 44°C needed less time to reach pH 4.6. Cooling gels after IMG resulted in an increase in G′ values at pH 4.6, a decrease in LT_max, WS, and B, and an increase in the area of protein aggregates of micrographs compared with the control gel made at constant IT of 37°C. Heating gels after IMG resulted in a decrease in G′ values at pH 4.6 and an increase in LT_max values and WS. The physical properties of acid milk gels were dominated by the temperature profile during the gel-strengthening phase that occurs after IMG. This study indicates that the final properties of yogurt greatly depend on the environmental conditions (e.g., temperature, time/rate of pH change) experienced by the casein particles/clusters during the critical early gel development phase when bonding between and within particles is still labile. Cooling of gels may encourage inter-cluster strand formation, whereas heating of gels may promote intra-cluster fusion and the breakage of strands between clusters.     

基于非靶向代谢组技术研究不同发酵温度酱油中代谢产物差异

目的 基于非靶向代谢组学研究不同发酵温度(25、30、35、40℃)酱油中代谢产物差异。方法 采用超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)检测不同发酵温度的酱油样品的代谢物,通过主成分分析(principal component analysis,PCA)、正交偏最小二乘判别分析法(orthogonal partial least square-discriminant analysis,OPLS-DA)等统计学分析,筛选不同温度发酵酱油的差异代谢物。结果 4种不同发酵温度酱油样品共鉴定出14类266个代谢物。其中,25℃下发酵酱油中氨基酸和有机酸类化合物的含量最高,而35℃发酵酱油的中氨基酸、脂肪酸类和生物碱化合物的相对含量最高。通过OPLS-DA分析研究,鉴定出了37种显著差异代谢物质(变量投影重要性>1),包括有氨基酸9种,糖类和有机酸各5种,生物碱和脂肪酸各4种,芳香类化合物3种,香豆素类、胺类和酚类各2种,黄酮类1种。结论 该研究明...     

Comparison of volatile metabolic profiles in fermented milk of Streptococcus thermophilus during the postripening period at different incubation temperatures

Streptococcus thermophilus has been extensively applied in fermented milk. This study used gas chromatography-ion mobility spectroscopy to determine and evaluate the volatile metabolites in raw milk, milk fermented at 37°C, and milk fermented at 42°C. Ten discriminatory volatile metabolites were identified at different incubation temperatures: acetone, 2-heptanone, 2-pentanone, 2-hexanone, butanal, hexanal, ethyl acetate, 3-methylbutanal, 3-methylbutanoic acid, and 2-methylpropanoic acid, indicating that fermentation temperature affected the spectrum of volatiles in milk fermented by different strains of S. thermophilus. Specifically, fermentation at 37°C led to accumulation of short-chain fatty acids, whereas fermentation at 42°C enriched ketones and other flavor substances in the fermented milk, enhancing the flavor of the product. This work examined the differences between the volatile metabolites produced by different S. thermophilus strains fermented at different temperatures to evaluate the effect of temperature on the metabolic pathways.     

不同温度对氮气气调锈赤扁谷盗各虫态致死时间比较研究

掌握温度对氮气气调中害虫不同虫态致死时间的影响程度对科学控制气调时间和成功杀虫具有重要意义。测定了18℃、23℃和28℃温度时锈赤扁谷盗的卵、幼虫、蛹和成虫在98%氮气气调过程中不同时间的死亡率及完全致死时间。温度18℃时锈赤扁谷盗卵、幼虫、蛹和成虫的完全致死时间分别为28、18、28和14 d,23℃时完全致死时间分别为22、14、24和8 d,28℃时完全致死时间分别为16、9、18和5 d。温度18℃时卵、幼虫、蛹和成虫的完全致死时间比23℃时相应延迟6、4、4和6 d,比28℃时相应延迟12、9、10和9 d。实验温度下98%氮气气调时锈赤扁谷盗耐受力最强的虫为蛹期,其后依次为卵、幼虫和成虫期。锈赤扁谷盗蛹在18、23和28℃温度下的死亡率-时间回归方程分别为y = 3.85x - 3.85、y = 4.01x - 3.53和y = 4.72x - 3.71。温度降低显著延迟98%氮气气调杀虫时间,氮气气调锈赤扁谷盗时应以杀死其耐受力最强的蛹为目标。     

Acid tolerance in Salmonella typhimurium induced by culturing in the presence of organic acids at different growth temperatures

The influence of growth temperature and acidification of the culture medium up to pH 4.25 with acetic, citric, lactic and hydrochloric acids on the growth and subsequent acid resistance at pH 3.0 of Salmonella typhimurium CECT 443 was studied. The minimum pH value which allowed for S. typhimurium growth within the temperature range of 25–37 °C was 4.5 when the pH was reduced using citric and hydrochloric acids, and 5.4 and 6.4 when lactic acid and acetic acid were used, respectively. At high (45 °C) or low (10 °C) temperatures, the growth pH boundary was increased about 1 pH unit. The growth temperature markedly modified the acid resistance of the resulting cells. In all cases, D-values were lower for cells grown at 10 °C and significantly increased with increasing growth temperature up to 37 °C, at which D-values obtained were up to 10 times higher. Cells grown at 45 °C showed D-values similar to those found for cells grown at 25 °C. The growth of cells in acidified media, regardless of the pH value, caused an increase in their acid resistance at the four incubation temperatures, although the magnitude of the Acid Tolerance Response (ATR) observed depended on the growth temperature. Acid adapted cultures at 10 °C showed D-values ranging from 5.75 to 6.91 min, which turned out to be about 2 times higher than those corresponding to non-acid adapted cultures, while higher temperatures induced an increase in D-values of at least 3.5 times. Another finding was that, while at 10 and 45 °C no significant differences among the effect of the different acids tested in inducing an ATR were observed, when cells were grown at 25 and 37 °C citric acid generally turned out to be the acid which induced the strongest ATR. Results obtained in this study show that growth temperature is an important factor affecting S. typhimurium acid resistance and could contribute to find new strategies based on intelligent combinations of hurdles, which could prevent the development or survival of Salmonella spp. in foods. The fact that moderately low temperatures (10 °C) markedly decrease the acid resistance and increase the growth pH boundary of S. typhimurium suggests the convenience to control the temperature during food processing as a strategy to prevent the growth and survival of this pathogenic microorganism.