Microwave Pre-treatment for Sun-Dried Raisins

Commercial sun-drying of raisins requires a long time, and chemical pretreatments are used to increase the drying rate. The feasibility of improving the sun-drying process of grapes by microwaves was investigated. Sultana seedless grapes, dipped in alkali solution, were pre-treated in a domestic microwave oven and dried by direct solar radiation. Microwave pre treatment reduced the moisture content by 10–20%. The microwave-treated grapes dried nearly two times faster than the controls. Blanching in boiling water had the same effect on the drying rate as microwaves. Color and appearance of treated grapes were comparable to commercial products.     

电子束辐照对无核葡萄干的杀灭霉菌效果及感官品质的影响

为有效控制无核葡萄干的霉菌,采用2、4、6、8、10 kGy的电子束对无核葡萄干进行辐照处理。同时,根据相关的标准,以色泽(权重为30%)、滋味(权重为35%)、气味(权重为35%)为评价指标,制订无核葡萄干的感官评价标准,并按此标准对辐照处理后的无核葡萄干进行感官品质评价。结果表明:经2 kGy辐照的样品感官评价结果与对照组无明显差异;经4、6、8、10 kGy辐照的样品感官评价结果低于对照组;无核葡萄干经6 kGy辐照,可杀灭100%的霉菌。     

Improving grape quality using microwave vacuum drying associated with temperature control

ABSTRACT:  Microwave (MW) vacuum dehydration using temperature to control the level of MW power demonstrated potential in improving the performance of the process. Product surface temperature measured by an infrared temperature sensor was used to control MW power at any level between 0 and 3 kW. Multiple linear regression analysis indicated an r ²= 0.942 for prediction of final moisture content and r ²= 0.985 for prediction of puffed character of grapes based on product temperature, time, specific energy, fresh fruit sugar, and fresh fruit moisture content. Temperature was found to be the most significant predictor. The elemental and compound contents of grapes dried using MW vacuum was compared to sun-dried raisins. The grapes dried using MW vacuum exhibited better preservation. Vitamin A was found in the MW-vacuum-dried grapes but none was detected in the raisins, and Vitamin C, thiamine, and riboflavin were also higher in the MW-vacuum-dried grapes than in the raisins.     

不同贮藏条件下油茶籽品质及生理活性

为了延长油茶籽的加工期限,将含水量为6%、13%的油茶籽分别贮藏在25℃、室温、4℃,相对湿度(RH)50%～65%条件下,观察贮藏期间品质及生理生化变化。结果表明：所有实验贮藏方法,油茶籽贮藏90d后均出现一定程度的劣变现象,贮藏品质下降。对不同处理贮藏效果的综合评价,最好的贮藏条件为温度4℃、油茶籽含水量6%,能明显抑制呼吸强度和脂肪酶活性,保持较高蛋白质、脂肪、糖等内含物质的含量,阻止油茶籽品质的劣变;其次为温度4℃、含水量13%,最差的为温度25℃、含水量13%。低温和低水分含量可有效提高油茶籽的贮藏品质。     

Effect of Storage Conditions on Quality Characteristics of Bologna Sausages Made with Citrus Fiber

ABSTRACT: Bologna sausage with added citrus fiber was improved nutritionally in fiber content and had decreased residual nitrite levels and a delay in the oxidation process as determined by TBA values and red color. Only TBA values and redness were influenced by storage conditions (light and darkness) mainly due to the oxidant effect attributable to light. In both cases these effects were minimized by the citrus fiber. Citrus fiber at all concentrations made the products harder and less springy and chewy. All samples had similar satisfactory quality scores except bologna with 2% citrus fiber, which had the lowest scores. Microbial growth was not modified by citrus fiber during storage.     

不同冷链贮运条件下冷鲜鸭肉品质变化

为研究不同冷链贮运条件对冷鲜鸭肉品质变化的影响,通过模拟产品冷链贮运过程中的环境,以感官评定、菌落总数和挥发性盐基氮(total volatile base-nitrogen,TVB-N)值为评定标准,研究了不同包装方式、运输时长、运输温度及运输途中的振动强度对冷鲜鸭肉品质的影响。结果显示,气调包装(53%O2+47%CO2)在贮运末期的TVB-N值仅为12.78 mg/100 g,仍处于二级鲜度,比真空包装和气调包装更能维持冷鲜鸭肉原有品质;运输1 h组在整个实验过程中感官评分值下降较慢,在实验末期其感官评分仍在8分以上;运输温度对产品贮运后期的菌落总数有显著影响(p<0.05),低温(4℃)运输能够有效地保持产品品质,比高温运输延长1~2 d贮藏期;振动强度对产品菌落总数有显著影响(p<0.05),3 Hz振幅对鸭肉品质影响较小,在贮藏末期菌落总数为5.04 lg CFU/g,TVB-N值为11.01 mg/100 g。本研究为冷鲜鸭肉冷链运输条件的选择提供了参考。     

瓶储存条件与乳制品感官品质相关性研究

选择了两种不同原料(A添加热稳定剂hs113、B未添加热稳定剂)的HDPE瓶分别放置1、3、5、7天,然后灌装乳酸菌饮料,分别在4℃冷藏12h、28℃存放8天、36℃存放8天,通过感官品评来确定不同瓶子原料A和B不同存放条件,HDPE瓶对乳酸菌饮料异味的影响程度。试验结果表明,28℃储存时样品的感官品质与瓶子放置天数无显著规律,在36℃储存时瓶子放置1天至3天内瓶味随时间延长有减弱趋势(5%显著水平上);A、B两种不同原料对产品的感官品质无明显差异(5%显著水平上)。     

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.     

不同贮藏条件下菠菜生鲜面的品质分析

以菠菜生鲜面为研究对象,以水分含量、水分活度、p H、酸度、色泽、叶绿素含量、感官属性、菌落总数为考核指标,在4℃和25℃条件下系统研究光照、避光、充CO2等3种贮藏方式对产品品质影响。实验结果:在4℃和25℃条件下,3种贮藏方式中菠菜生鲜面的水分含量、水分活度、p H、色泽、叶绿素含量、感官属性随贮藏时间的延长逐渐下降,酸度和菌落总数逐渐上升;4℃、充CO2的贮藏方式,产品的品质最优;贮藏5 d的感官评分和菌落总数分别为7.1、8.7×104CFU/g,为产品的品质裂变转折点;菠菜生鲜面感官品质、菌落总数与产品的水分含量、酸度、水分活度、p H、总叶绿素、叶绿素a、叶绿素b、L*、a*、b*具有相关性。本研究通过对贮藏品质的探讨,为产品的货架期延长、突破制约产业化发展的技术瓶颈提供重要的数据支撑。     

Raisins and Oral Health

Traditionally, raisins have been thought to promote dental caries due to their suspected “stickiness” and sugar content. Current research identifies some evidence contrary to traditional thought, suggesting that raisins may not contribute to dental caries. This article reviews new findings with regards to raisins and the 3 conditions that are thought to contribute to the formation of dental caries; low oral pH, adherence of food to teeth, and biofilm (bacterial) behavior. The studies reviewed concluded that raisin: consumption alone does not drop oral pH below the threshold that contributes to enamel dissolution, do not remain on the teeth longer than other foods, and contain a variety of antioxidants that inhibit Streptococcus Mutans, bacteria that is a primary cause of dental caries. Further research in this area should be considered.     

贮藏条件对不同工艺生产的油茶籽油品质的影响

对不同工艺生产的油茶籽油,在不同贮藏条件下长期贮藏后的酸值、过氧化值和VE含量进行测定。结果
表明：各种成品油的酸值和过氧化值随贮藏时间的延长而上升,而VE的含量下降。全程低温工艺精炼的油茶籽油
经过长期贮藏后,其酸值和过氧化值的增加量与一级压榨油相当,但明显低于高温精炼油。在高温、光照等不良贮
藏条件下,低温工艺精炼的油茶籽油的优势很明显,品质劣变程度小。     

不同包装条件对米糠贮藏稳定性的影响

米糠资源营养丰富,具有很高的开发利用价值,但其贮藏稳定性差导致品质迅速下降。本实验以米糠为研究对象,分析自然贮藏条件下采用PE、PE/PA及编织袋包装的米糠在常压密封、真空密封条件下主要品质指标变化。结果发现：贮藏30d后,PE/PA/真空组水分含量下降0.99%,粗脂肪含量下降3.74%,脂肪酸值升高77.7mg KOH/100g,而对照组相应指标分别为PE/PA/真空组的3.6、2、5.33倍;PE/PA/真空组VE、γ-谷维素含量分别下降了0.4mg/100g、0.01%,对照组降幅分别是PE/PA/真空组的2.78倍和6倍;菌落总数PE/PA/真空组由初期的2.82×108CFU/g减少到0.3×107CFU/g,性状保持良好,具有米糠特有的香味,而对照组菌落总数增加到1.8×1010CFU/g,且出现明显的霉味,颜色变深,结块严重。结果表明不同包装对提高米糠贮藏稳定性效果依次为：PE/PA/真空＞PE/PA/常压＞PE/真空＞PE/常压＞编织袋＞对照,各样品结果呈显著差异(P＜0.05)。采用PE/PA真空包装贮藏能有效提高米糠贮藏期品质稳定性。     

不同葡萄品种加工绿葡萄干的适宜性分析

以36个新疆绿色葡萄品种为试材进行感官、理化指标的检测,运用灰色关联度分析方法,对其主要性状与"理想品种"性状之间的密切程度进行综合分析,依据各品种的加权关联度对参试品种进行聚类分析,研究其加工绿葡萄干的适宜性。结果表明:无核白、底莱特、京早晶、波尔莱特、无核白鸡心等葡萄品种适宜加工绿葡萄干,而苏珊玫瑰、谢克兰格、匈牙利之光等则不适宜加工成绿葡萄干,其他品种居中。此结果与各品种实际表现基本一致,说明该方法可用于我国葡萄干产业加工品种的筛选及其评价体系的建立。     

In Vitro Iron Bioavailability and Antioxidant Activity of Raisins

ABSTRACT: Iron bioavailabilities and antioxidant activities of 3 generic raisin types-Golden Thompson, Dipped Thompson, and Sun-dried Thompson-were quantified and compared. Iron bioavailability was assessed with an in vitro digestion/Caco-2 cell culture model using cell ferritin formation as an index of iron bioavailability. Antioxidant activity was determined using the total oxyradical-scavenging capacity (TOSC) assay. Ferritin formation in Caco-2 cells was low for all 3 raisin types, indicating low iron bioavailability. Ethylenediaminetetraacetic acid (EDTA) enhanced iron bioavailability from raisins but ascorbic, citric, and tartaric acids showed no effect. Antioxidant activity was significantly higher in Golden Thompson than Dipped Thompson and Sun-dried Thompson, suggesting that enzymatic browning negatively affected antioxidant activity.     

响应面法优化超声波辅助清洗无核绿葡萄干工艺

针对葡萄干加工企业清洗无核绿葡萄干后无核绿葡萄干极易褐变的问题,采用超声波辅助清洗工艺,在单因素实验基础上,选择清洗剂酒精度、清洗温度和清洗时间为影响因子,褐变指数BI值为指标,通过响应曲面法设计和分析,最佳清洗条件下清洗的葡萄干用热泵干燥。实验表明无核绿葡萄干超声波辅助清洗工艺的最佳条件:清洗剂酒精度44%vol、清洗温度9 ℃、清洗时间90 s,在此条件下,无核绿葡萄干BI值仅为33.43,较传统自来水喷淋清洗降低26.98%。热泵干燥葡萄干的最佳温度是50 ℃,无核绿葡萄干BI值仅为23.69,略低于未清洗无核绿葡萄干,较相同温度下热风干燥降低28.52%。     

An After‐School Snack of Raisins Lowers Cumulative Food Intake in Young Children

Snacks are an important part of children's dietary intake, but the role of dried fruit on energy intake in children is unknown. Therefore, the effect of ad libitum consumption of an after‐school snack of raisins, grapes, potato chips, and chocolate chip cookies on appetite and energy intake in twenty‐six 8‐ to 11‐y‐old normal‐weight (15th to 85th percentile) children was examined. On 4 separate weekdays, 1 wk apart, children (11 M, 15 F) were given a standardized breakfast, morning snack (apple), and a standardized lunch. After school, children randomly received 1 of 4 ad libitum snacks and were instructed to eat until “comfortably full.” Appetite was measured before and 15, 30, and 45 min after snack consumption. Children consumed the least calories from raisins and grapes and the most from cookies (P < 0.001). However, weight of raisins consumed was similar to potato chips (about 75 g) and lower compared to grapes and cookies (P < 0.009). Raisins and grapes led to lower cumulative food intake (breakfast + morning snack + lunch + after‐school snack) (P < 0.001), while the cookies increased cumulative food intake (P < 0.001) compared to the other snacks. Grapes lowered appetite compared to all other snacks (P < 0.001) when expressed as a change in appetite per kilocalorie of the snack. Ad libitum consumption of raisins has potential as an after‐school snack to achieve low snack intake prior to dinner, similar to grapes, compared to potato chips, and cookies in children 8 to 11 y old.     

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.     

贮藏条件对斑点叉尾鮰液体鱼蛋白品质的影响

以斑点叉尾鮰和经90℃加热处理的斑点叉尾鮰为原料分别制备液体鱼蛋白,并置于6、10、15、20、30、40℃条件下贮藏40d。分析测定40℃条件下贮藏5、10、20、40d 的液体鱼蛋白粗成分,40℃条件下贮藏40d 的液体鱼蛋白的氨基酸组成、微量元素含量和新鲜原料制备当天及贮藏第1、2、3、4、5、10、20、40d的液体鱼蛋白样品中蛋白质水解度和酸溶性蛋白含量。结果表明,斑点叉尾鮰液体鱼蛋白在40℃条件下贮藏40d后,与原料液体鱼蛋白相比,其蛋白质含量提高了12g/kg,而脂肪、灰分和水分的含量则分别降低了3、3、31g/kg;氨基酸种类及含量、无机元素含量未发生明显变化;水解度、酸溶性蛋白含量随贮藏条件的不同而各异;经加热处理的斑点叉尾鮰液体鱼蛋白的水解度、酸溶性蛋白含量不受贮藏条件的影响。