即食液熏鲍鱼生产工艺开发与优化

目的 开发与优化即食液熏鲍鱼生产工艺。方法 以感官评分为指标,通过正交实验,研究液熏液配方和浸渍烘干工艺参数对即食液熏鲍鱼品质的影响。结果 即食液熏鲍鱼最佳生产工艺为[液熏液配方为食用盐添加量(2 %)、白砂糖添加量(10 %)、酱油添加量(3.5 %)、烟熏香味料添加量(0.2 %)和浸渍烘干工艺参数为浸渍时间(2 h)、浸渍温度(60 ℃)、烘干时间(2 h)、烘干温度(80 ℃)];在此最佳生产工艺下加工而成的即食液熏鲍鱼的理化、微生物及污染物指标符合相关食品安全国家标准。结论 开发并优化了一种即食液熏鲍鱼生产工艺,为鲍鱼休闲食品的深加工提供了参考依据。     

基于高效液相色谱法的麻辣火锅底料辣度分级模型建立及其在熬煮过程中的变化

基于高效液相色谱法结合感官评价结果,采用SPSS中的Fisher判别分析方式,对火锅底料进行辣度分级,得到麻辣火锅底料的辣度分级模型;研究熬煮过程中辣椒素类物质（capsaicinoids,Cap-S）的含量变化,得到其影响辣度分级的规律。结果表明,仅用感官评价对火锅底料进行辣度分级受感官评价人员的影响较大,结论准确度不高;若以火锅底料中Cap-S含量为分级标准,其正判率界值为24%＞20%,可以很好地将辣度分为5 个等级,分级模型较为合理。火锅底料熬煮过程会影响Cap-S的迁移,Cap-S在油相和水相中处于动态平衡状态,同时调味料中的Cap-S逐渐迁移到汤底中,使得熬煮过程中辣度总是不断发生变化。高效液相色谱法结合感官评价结果对火锅底料进行辣度分级,可以很好地区分火锅底料的辣度,指导消费者购买合适的食品。     

毛火后闷堆处理对夏季红茶品质的影响

以茶树品种‘碧香早’夏季一芽二叶为原料,在传统红茶加工工艺基础上,将毛火初干后的闷堆工艺引入红茶加工的干燥工艺中,从感官品质、滋味品质成分和香气品质成分3 方面探讨毛火初干后的闷堆处理对红茶品质的影响。结果表明,与传统工艺加工的红茶相比,毛火初干后闷堆3 h,能显著提高红茶品质,滋味醇爽,汤色红橙明亮,甜香显露;茶样中茶黄素质量分数显著增加（P＜0.05）,由0.41%增加到0.62%;醇类香气物质总相对含量由52.25%上升到57.33%,酮类香气物质增加了具有果香的1,3,7-三甲基-3,7-二氢-1H-嘌呤-2,6-二酮、4-[2,2,6-三甲基-7-氧杂二环[4.1.0]庚-1-基]-3-丁烯-2-酮和6-甲基-5-庚烯-2-酮。由此提示毛火初干后的闷堆工艺技术在提高红茶品质的生产实践中具有可行性。     

真空冷冻干燥制备即食小米粥工艺优化

探索最佳即食小米粥开发工艺及真空冷冻干燥工艺。筛选出适合开发即食小米粥的小米品种,采用模糊数学感官评价法和响应面法优化即食小米粥工艺,正交法优化真空冷冻干燥工艺。结果表明：东方亮小米适合开发即食食品;即食小米粥开发最佳工艺条件为浸泡时间40 min,料液比(g/mL)1:20,熬煮时间30 min,此时得到复水率为14.74,模糊感官评分为90.5;真空冷冻干燥最佳加工条件为物料填充高度3 cm,升华温度40℃,解析温度65℃,此时干燥速率为3.92%。     

Effects of dry cow grouping strategy and prepartum body condition score on performance and health of transition dairy cows

Multiparous Holstein cows (n = 337) on two commercial dairy farms were used to determine the effects of feeding a close-up diet for 21 (treatment S) or 60 d (treatment L). Milk yield was not affected by treatment; however, cows fed treatment S tended to have increased yields of fat, 3.5% fat-corrected milk, and protein during the first 5 mo of their subsequent lactation compared to treatment L. Cows fed treatment L gained more body condition score (BCS) during the dry period and had longer days to first service. As a secondary objective, relationships of BCS at dry off and subsequent performance were evaluated. Cows with initial BCS < or =3.0 (thinner) tended to produce more milk during early lactation than cows with initial BCS > or = 3.25 (fatter). A trend for an interaction of treatment and initial BCS existed for milk yield such that thinner cows fed treatment S produced the most milk and fatter cows fed treatment S produced the least amount of milk; cows fed treatment L regardless of BCS produced an intermediate amount of milk. Subsequent reproductive performance was similar among thinner and fatter cows. These data indicate that 2 group nutritional strategies for dry cows are preferred, and BCS at dry off should be considered when determining grouping and nutritional strategies for dry cows. Furthermore, moderately thin cows at dry off do not have impaired performance during their subsequent lactation compared to cows of greater BCS.     

Questionnaire Design: Carry‐Over Effects of Overall Acceptance Question Placement and Pre‐evaluation Instructions on Overall Acceptance Scores in Central Location Tests

Question placement and usage of pre‐evaluation instructions (PEI) in questionnaires for food sensory analysis may bias consumers’ scores via carry‐over effects. Data from consumer sensory panels previously conducted at a central location, spanning 11 years and covering a broad range of food product categories, were compiled. Overall acceptance (OA) question placement was studied with categories designated as first (the first evaluation question following demographic questions), after nongustation questions (immediately following questions that do not require panelists to taste the product), and later (following all other hedonic and just‐about‐right [JAR] questions, but occasionally before ranking, open‐ended comments, and/or intent to purchase questions). Each panel was categorized as having or not having PEI in the questionnaire; PEI are instructions that appear immediately before the first evaluation question and show panelists all attributes they will evaluate before receiving test samples. Postpanel surveys were administered regarding the self‐reported effect of PEI on panelists’ evaluation experience. OA scores were analyzed and compared (1) between OA question placement categories and (2) between panels with and without PEI. For most product categories, OA scores tended to be lower when asked later in the questionnaire, suggesting evidence of a carry‐over effect. Usage of PEI increased OA scores by 0.10 of a 9‐point hedonic scale point, which is not practically significant. Postpanel survey data showed that presence of PEI typically improved the panelists’ experience. Using PEI does not appear to introduce a meaningful carry‐over effect.     

Identifying drivers for consumer acceptance and purchase intent of corn tortilla

ABSTRACT:  The traditional production of corn tortilla has been modified by new processing technologies to make possible a commercial-scale production; this practice has resulted in products having sensory properties different from those produced by the traditional method. There is no published information on sensory attributes driving acceptance and purchase intent of corn tortillas. Identifying sensory drivers for acceptance and purchase intent of corn tortillas will help commercially produce products that satisfy consumers' expectations. A consumer study was conducted to evaluate acceptance and purchase intent of corn tortillas and determine drivers of acceptance and purchase intent of the products. Ten samples of corn tortillas were selected to represent a variety of corn tortillas available in the Mexican market. Three hundred Mexican consumers evaluated acceptability of appearance, color, thickness, rollability, resistance to tearing, aroma, chewiness, taste and aftertaste, and overall liking using a 9-point hedonic scale. Overall acceptance and purchase intent were determined with a yes/no scale. Analysis of variance and multivariate analysis of variance revealed that consumers were able to differentiate differences in sensory acceptability among 10 samples. For example, 2 homemade and 1 small commercial-scale samples, with an overall liking score of 6.6 to 6.7, were more acceptable than others. Rollability, resistance to tearing, and chewiness were attributes underlying overall differences among 10 samples. Attributes determining overall acceptance of corn tortillas were chewiness and overall liking. Purchase intent was influenced by overall appearance, rollability, chewiness, taste, and overall liking. This study revealed critical sensory attributes and their weights given by Mexican consumers when making decisions for acceptance and purchase intent of corn tortilla.     

6类常见食品中含硫化合物风味特征及形成机理研究进展

挥发性含硫化合物广泛存在于多种食品中,具有阈值极低的特点,是对食品感官品质有重要贡献的特征风味组分,在形成食品独特风味特征中也起着至关重要的作用。不同种类的含硫化合物表现出的食品风味特征不尽相同,不同含量的含硫化合物对食品感官品质的影响也差异显著,因此,对感官风味受含硫化合物影响较大的6类常见食品中含硫化合物风味特征及其形成机理进行了研究。牛奶中主要含硫化合物是甲硫醇和二甲基三硫醚,通常表现为蒸煮味;2-甲基-3-呋喃硫醇是牛肉的关键含硫化合物,呈现为焙烤香和肉香;糠硫醇的焙烤香、3-巯基己烷-1-醇的果香是酒类中的关键风味组分;1,2,3,5,6-五硫杂环庚烷是呈现香菇独特气味的关键化合物;二丙基二硫醚、二甲基三硫醚和大蒜素分别为大葱、洋葱和大蒜风味形成的关键含硫化合物;二甲基硫醚和二甲基三硫醚是菜籽油呈现辛辣刺激风味的主要原因。含硫化合物主要是由含硫前体物质在微生物或酶的降解作用下形成,同时有些含硫化合物也产生于美拉德反应。通过对6类常见食品中含硫化合物的种类、对食品感官品质的影响及其形成机制进行全面介绍,总结常见食品中含硫化合物的风味及其对食品感官品质影响的一般规律,旨在为食品中含硫化合物形成机理及风味特征的进一步研究提供参考。