Microwave vacuum drying of osmotically dehydrated mandarin cv. (Sai‐Namphaung)

Mandarin [mandarin cv. (Sai‐Namphaung)] was subjected to osmotic dehydration prior to microwave vacuum drying. Osmotic solutions were varied using different ratios of sucrose to glycerol (9:1, 7:3 and 5:5 w/w). Because of the decreased moisture content and solid gain during osmotic dehydration, dielectric properties of mandarin were changed significantly (P ≤ 0.05). The osmotically dehydrated mandarin was then dried further using microwave vacuum drying at 4.8 and 6.4 W g^?1. Among thin layer models, page model was the best to describe the drying of osmotically dehydrated mandarin. An increase in the microwave power could increase drying rate without significant effect on hardness of dried samples. Nonetheless, the hardness was significantly (P ≤ 0.05) reduced by an increase in the glycerol ratio in the osmotic solution. The increase in microwave power and glycerol ratio significantly (P ≤ 0.05) decreased β‐carotene content and thereby affected colour of the dried mandarin.     

Mandarin fruit quality: a review

During the last decade, there has been a continuous rise in consumption and global marketing of fresh, easy‐to‐peel mandarins, with current annual production of nearly 29 million tons. Nevertheless, most of the existing knowledge on quality traits of citrus fruit comes from research conducted on oranges and grapefruit, which are the main products for the citrus juice manufacturing industry; relatively little is yet known regarding the unique fruit quality traits of mandarins, nor about the great diversity in these traits among the various natural sub‐groups and varieties of mandarins. In the present review we discuss the physiological, biochemical, and molecular factors governing key fruit quality attributes of mandarins, including fruit colour, size and shape, ease of peeling, seedlessness, flavour, and nutritional quality. Fruit colour, size, and shape contribute to external appearance; peelability and seedlessness to ease of consumption; and flavour and nutritional quality to internal quality. © 2017 Society of Chemical Industry     

基于电子鼻评价不同贮藏期蜜桔鲜榨汁品质的研究

为建立一种快速无损检测蜜桔鲜榨汁品质的方法,将宫川蜜桔(satsuma mandarins)置于20℃、相对湿度85%条件下贮藏,每3 d随机选取10个果实制成汁,利用PEN3电子鼻检测其香气,同时测定其主要品质指标并进行相关性分析。通过主成分分析(Principal Component Analysis,PCA)、线性判别分析(Linear Discriminant Analysis,LDA)对不同贮藏时间的蜜桔进行区分。结果显示:电子鼻传感器响应值与蜜桔鲜榨汁可溶性固形物含量和VC含量显著相关;线性判别分析能较好地区分出不同贮藏时间的蜜桔;负荷加载分析(Loading analysis)结果显示,传感器W1S(主要对甲烷灵敏)、W2S(对乙醇灵敏,也对部分芳香型化合物灵敏)和W2W(对芳香成分和有机硫化物灵敏)在蜜桔鲜榨汁品质评价中起主要作用。结果表明利用电子鼻技术有望实现对蜜桔鲜榨汁品质的快速无损检测。      

蓝桉叶精油对砂糖橘的保鲜效果

旨在探明蓝桉叶精油对耐藏性较差的砂糖橘的保鲜效果。采用0.25%、0.50%、0.75%和1.00%四种浓度蓝桉叶精油乳液浸泡砂糖橘60 s,在常温下贮藏,定期进行检测,通过生理生化指标及好果率对保鲜效果进行评价。研究结果表明,与对照相比,蓝桉叶精油处理可显著降低采后砂糖橘的呼吸强度,有效延缓砂糖橘果肉中总糖、VC和可滴定酸(TA)含量的下降速率,明显减少砂糖橘的腐烂损失,有效提高其果皮超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性。四种不同浓度蓝桉叶精油处理相比,0.75%处理组的保鲜效果要明显好于其它处理组,而1.00%处理组可能存在轻微药害。研究结果提示,蓝桉叶精油是一种极具开发利用潜力的砂糖橘天然保鲜剂。      

Automatic context induction for tone model integration in mandarin speech recognition

Tone model (TM) integration is an important task for mandarin speech recognition.It has been proved to be effective to use discriminatively trained scaling factors when integrating TM scores into multi...     

β—环状糊精在食品工业中的应用试验

本文对环状糊精在柑桔罐头除苦、蛋糕保鲜和固体香油中的应用进行了介绍和试验。     

Effects of Polymorphisms in Pepsinogen (PEP), Amylase (AMY) and Trypsin (TRY) Genes on Food Habit Domestication Traits in Mandarin Fish

Mandarin fish (Siniperca chuatsi) have a peculiar feeding habit of only accepting live fish prey and refusing dead prey and artificial diets. However, previous research has shown that some individuals accept dead prey after gradual domestication. Digestive enzymes are correlated with feeding habits in fish. In the current study, SNPs in the mandarin fish genes for pepsinogen (PEP), amylase (AMY), and trypsin (TRY) were evaluated for associations with feeding habits in domesticated mandarin fish by scanning their complete genomic sequence. In total, two SNPs were found in PEP, one was found in TRY, and none were found in AMY. The D1(CTCC) and D5(TTTT) diplotypes in the PEP gene tended to show strong effects on the feeding habits of domesticated fish (p < 0.01). The results indicate that PEP may be associated with the genetic mechanism for feeding habits in mandarin fish, and the D1(CTCC) and D5(TTTT) diplotypes in the PEP gene may be useful markers for selecting mandarin fish with appropriate feeding habits for domestication.     

响应面优化鳜鱼致敏蛋白的木瓜蛋白酶水解工艺

为寻找降低淡水鱼致敏的有效方式,对鳜鱼致敏蛋白在酶解过程中抗原活性的变化情况进行研究。采用中性甲醛电位滴定法和间接酶联免疫吸附法测定木瓜蛋白酶水解鳜鱼蛋白后的水解度和抗原降低率。通过单因素试验和响应面分析研究酶解时间、酶用量、酶解温度、体系pH值以及各因素交互作用对水解度利抗原降低率的影响。模拟得到二次多项式回归方程的预测模型,并确定鳜鱼鱼肉蛋白最佳水解工艺条件:体系pH值为8.00的磷酸盐缓冲液,木瓜蛋白酶的酶用量为2940U/g,酶解时间4h,控制酶解温度为40℃。在此条件下,水解度和抗原降低率理论值为35.93%和56.78%,实测值为36.67%和58.33%。理论值和实测值之间相差较小,模型优化合适。     

壳聚糖-纳米纤维素复合涂膜对砂糖橘贮藏保鲜效果的影响

为探究纳米纤维素（nanocrystal cellulose,NCC）的添加对壳聚糖涂膜保鲜效果的影响,本研究采用纯壳聚糖（chitosan,CS）涂膜液以及NCC质量分数为2%和4%的CS-NCC复合涂膜液（CS-2% NCC和CS-4% NCC）分别对砂糖橘进行涂膜,并以咪酰胺（prochloraz,PCZ）处理组和未处理组（CK组）为对照,测定各组果实在贮藏期间的质量损失率、腐烂率、营养品质指标、果皮中丙二醛含量以及抗氧化酶活力,并进行果皮表面微观形态的观察。结果表明,复合涂膜不能降低果实的质量损失率,但其对腐烂的抑制效果总体好于CS组和PCZ组;在贮藏24 d时,与CK组相比,CS-4% NCC组的腐烂率降低了50%;同时,涂膜可有效保持可滴定酸、可溶性固形物、总酚和可溶性蛋白等营养物质的含量;CS-4% NCC组果皮中的丙二醛含量最低,且该组在贮藏期间可维持较高的过氧化物酶与过氧化氢酶活力,说明CS-4% NCC复合涂膜可明显延缓果实的膜脂过氧化,从而使果实保持较好的抗衰老能力;从涂膜的微观形态可看出,果皮表面的涂膜在贮藏第1天便出现微孔,添加4%的NCC有助于减少微孔的出现,增强涂膜的结构稳定性。综上,添加NCC可改善CS涂膜的结构和性能,显著增强其对果实的保鲜效果。添加4% NCC的复合涂膜在抑制果实腐烂和保持果实品质方面与PCZ处理的效果接近,因此该复合涂膜有望替代化学保鲜剂在砂糖橘等柑橘果实的保鲜中进行应用。