Effect of pH on ochratoxin A production by Aspergillus niger aggregate species

The effect of pH (2-10) on growth and ochratoxin A (OTA) production by 12 Aspergillus niger aggregate strains was studied in two culture media: Czapek yeast autolysate agar (CYA) and yeast extract sucrose agar (YES), over 30 days. The strains were selected to include different sources, different reported abilities to produce OTA and different ITS-5.8S rDNA RFLP patterns. YES was a better culture medium than CYA for OTA production. In this medium, OTA was produced from pH 2 or 3 to 10 depending on the strain. The results show the ability of A. niger aggregate strains not only to grow, but also to produce OTA over a wide pH range. The results will lead to a better understanding of the role of A. niger aggregate strains in the OTA contamination of several food commodities.     

Influence of yeast on the yield of fermentation and volatile profile of ‘Węgierka Zwykła’ plum distillates

The character of plum brandies depends on a unique aroma profile of the plum and the microbiota present on the surface of the fruits, as well as yeast used for fermentation. In this study, an evaluation of the effect of microorganisms applied for the fermentation of W?gierka Zwyk?a var. plum mashes and processing temperature (18 °C, 30 °C) on its efficiency and volatile profile, as well as taste and flavour of distillates obtained was performed. An estimation of the odour activity values (OAVs) of the volatile compounds was also conducted. Regardless of whether the fermentation was carried out using Saccharomyces bayanus wine yeast or by native microflora present on plums as well as raisins, the efficiency of this process was high and ranged between 91.7 and 96.7% of the theoretical efficiency. Especially rich in esters (among others ethyl acetate and isoamyl acetate) was the distillate derived after fermentation with the microflora of plums and raisins, at 18 °C. An evaluation of the individual aromatic effect of chemical compounds present in tested distillates, in terms of their OAVs, revealed that the highest OAVs were reached with isovaleraldehyde. Other compounds that showed aroma values >1 and possibly had an effect on the overall aroma of tested plum distillates were the following: hexanal, benzaldehyde, ethyl acetate, isoamyl acetate, ethyl benzoate, ethyl hexanoate, 1‐propanol, 2‐methyl‐1‐butanol, 3‐methyl‐1‐butanol and 1‐hexanol. The performed sensory ranking showed that the best rated distillate was the one obtained after fermentation with the indigenous microflora of plums and raisins, at 18 °C. Copyright © 2016 The Institute of Brewing & Distilling     

新疆干果复合饮料的研制

以杏干、酸梅、红枣和葡萄干为原材料,按照合适的比例浸泡,提取浸提液研制干果复合饮料。以40℃的温开水对干果进行浸泡,采用正交实验筛选最佳原材料进行配比及稳定剂和护色剂的最佳添加量。用手持式糖度计、酸度计、高效液相色谱分析仪以及原子吸收光谱仪,分别检测复合饮料中的糖度、酸度、Vc含量和微量元素的含量。实验结果表明:在400mL、40℃的温开水中浸泡25g杏干、20g酸梅、15g红枣和10g葡萄干为复合饮料最佳配方,浸泡时间为24h,添加的稳定剂为0.2%的羧甲基纤维素钠和0.03%的黄原胶,0.02%的柠檬酸,测得复合饮料中糖含量为5.3%,酸度为3.68,Vc的含量为2.469mg/100mL,锌的含量为0.386mg/100mL,铁的含量为0.678mg/100mL。     

Raisin Consumption by Humans: Effects on Glycemia and Insulinemia and Cardiovascular Risk Factors

Raisins are widely recommended as good foods and preferred snacks because of their nutrient content. They are rich in dietary fiber, potassium, and many health‐promoting phytonutrients and antioxidants. Raisins have a high dietary fiber score. Laboratory studies document that raisins rank in the upper quartile of foods for antioxidant content. Clinical research related to the potential health benefits of raisins has intensified over the past 10 y. Much of this research has focused on blood glucose and insulin responses to raisins compared to other foods or snacks. Meal studies indicate that raisins have a low to moderate glycemic index and a low insulinemic index. Longer term studies suggest that customary intake of raisins is associated with lower postprandial blood glucose values than with equicaloric control foods. Cross‐sectional studies suggest that higher levels of dried fruit consumption are associated with lower systolic and diastolic blood pressure than seen with minimal dried fruit use. One clinical study documents that raisin intake over 12 wk is accompanied by a significant reduction in blood pressure. Preliminary results indicate that raisins are associated with increased satiety and decreased food consumption over an 8‐h period, but the potential benefits of raisins for weight loss have not been assessed. Raisin intake is accompanied by reductions in serum low‐density lipoprotein cholesterol, triglycerides, and oxidized low‐density cholesterol values. Thus, raisins have the potential to significantly reduce the risk for developing diabetes or cardiovascular disease.     

Five-year survey of ochratoxin A in processed sultanas from Turkey

The results of surveillance for ochratoxin A (OTA) in 1885 samples of sultanas taken during five crop years between 1999 and 2003 are reported. The analytical method was based on extraction with methanol + sodium bicarbonate and clean-up by immunoaffinity column chromatography followed by high-performance liquid chromatography with fluorescence detection. The limit of detection for OTA was 0.3 µg kg^-1. The results show that 9.3% of the samples contained no detectable levels of OTA, whereas 0.6% had concentrations exceeding 10 µg kg^-1; the remaining 90.3% had levels within the range 0.3-10 µg kg^-1. The overall mean OTA concentration in the total number of 1885 samples taken was 1.36 ± 2.91 µg kg^-1; the overall median was calculated as 0.90 µg kg^-1.     

The sensory attributes of cakes containing large numbers of low sugar raisins, as evaluated by consumers and a trained sensory panel

The sensory attributes of cakes, containing a greater number of low sugar raisins (LSR) than that normally used, were evaluated by two different groups of trained and untrained panellists. The purpose of this sensory evaluation was to find out whether such bakery products were more attractive to consumers than normal cakes and could be further promoted in the market. Cakes containing LSR and additional lemon peel scored more poorly than cakes containing only raisins, both in terms of taste and overall preference. Cakes containing only LSR had good sensory characteristics and could be considered as competitive products when compared with similar products already on the market. Young people found cakes with raisins tasty, but they did not consume them readily. The special advantages of these cakes are their natural ingredients, raisins with lower amount of sugars, good taste and high quality, all of which should be emphasized to make them attractive in the market.     

Antimicrobial Properties of Raisins in Beef Jerky Preservation

: Fruits and vegetables may contain components that exert antimicrobial effects. In this study, beef jerky formulated with 15% raisins produced conditions inhibitory to pathogenic bacteria by decreasing pH to 5.4 and a_w to 0.64. Storage of vacuum‐packaged raisin‐beef‐jerky (10‐wk; 30 °C) resulted in a further decrease to pH 4.5 and a_w to 0.62. The antioxidant potential was increased by over 600%. The product received favorable sensory ratings for appearance, texture, and flavor, comparable to the non‐raisin control. Raisins in ready‐to‐eat meats such as jerky produce a lower fat, higher fiber product with antimicrobial capability and increased antioxidant potential, thereby providing a potentially safer, healthier alternative to traditional meat snacks.     

Raisin processing: physicochemical,nutritional and microbiological quality characteristics as affected by drying process

Processing and conservation of grapes by suitable techniques has been a major challenging issue for a long time. Optimization of drying and pretreatment operations of this fruit have been extensively studied. However, in order to achieve the production of high-quality raisins and reach consumers’ acceptance, special attention for quality attributes should be taken into account. Quality characteristics of grapes such as color, texture, vitamins, phytochemicals, aroma profile and microbial stability are of paramount importance since they could vary throughout the dehydration procedure and would directly determine quality perception and consumer choice. This paper presents a comprehensive review of the physicochemical, nutritional and microbiological characteristics of dried grapes as affected by the drying process. In addition, it investigates the changes of different grapes quality attributes (mainly nutritional and aromatic proprieties) during processing, which enables professionals and scientists to better choose and optimize grape processing to deliver the highest raisin quality to consumers.     

Ochratoxin A in dried vine fruits on the Canadian retail market

Between 1998 and 2000, 151 samples of raisins and sultanas and two samples of currants were collected from retail outlets across Canada and analysed for ochratoxin A. Samples were extracted with methanol-sodium bicarbonate, and the extracts were cleaned-up by immunoaffinity column chromatography. Ochratoxin A was quantified by liquid chromatography with fluorescence detection. The minimum quantifiable level was 0.1 ng g^-1. Ochratoxin A was present, above the minimum quantifiable level, in 67 (79%) of 85 samples of raisins, in 39 (59%) of 66 samples of sultanas, and in both samples of currants. The overall mean level of ochratoxin A was 1.8 ng g^-1 in both the raisins and sultanas, and 2.8 ng g^-1 in the currants.