微波预处理对生鲜花生贮藏特性和品质的影响

为了研究微波预处理对生鲜花生贮藏特性和品质的影响,采用不同功率强度微波(0.55、0.85、1.15 W/g)对鲜食花生处理120 s后置于(10±1)℃条件下进行贮藏。结果表明：适宜功率强度的微波处理可有效抑制生鲜花生的发芽率和霉变率,同时抑制生鲜花生的呼吸强度,降低失重率,降低膜脂过氧化程度,延缓生鲜花生的衰老和品质劣变;微波处理对生鲜花生还有一定杀菌作用,微波功率强度越大,杀菌效果越好。综合分析,0.85 W/g功率强度微波预处理组的生鲜花生贮藏品质最佳。     

红碎茶在贮藏过程中内含成分的变化和品质的变异

前言茶叶从生产加工到销售流通,直至消费,大都需要几个月的时间,有些甚至要跨年度。在这段时间内,就有一个贮藏过程。在贮藏过程中,将要发生一系列复杂的物理、化学变化,变化过量就会导致品质劣变,出现陈味、异味和霉变,使茶叶的饮用     

茶叶贮藏过程中品质变化及其影响因素研究进展

本文介绍了茶叶贮藏过程中,温度、湿度、光照和氧气等外界环境因素对其品质的影响,以及贮藏中茶叶品质成分,如含水量、氨基酸、茶多酚、叶绿素和维生素等的变化;并对目前生产与研究提出了初步想法。     

游离脂肪酸组成在绿茶贮藏中的变化

游离脂肪酸是构成茶叶香气的重要化学基础,但长期以来由于分析检测技术等问题,对茶叶加工和贮藏中游离脂肪酸的研究尚不多见。本文试图就绿茶贮藏中游离脂肪酸组成的变化与茶叶品质的关系以及贮藏条件的影响作用,进行一些探讨。一、游离脂肪酸组成与绿茶品质变化的关系     

绿茶贮藏过程中茶多酚含量的变化与感官品质的关系

分析了大叶种绿茶贮藏过程中多酚类与茶叶感官品质的关系。结果表明,多酚类下降率与滋味、汤色、香气得分的下降率基本一致;当多酚类下降5％时,即能引起茶叶汤色、滋味、香气的明显下降．当下降率达到25％时．茶叶质变严重,失去原有饮用价值。因此,可以考虑将茶多酚作为绿茶质变的化学指标。     

不同茶树品种制绿茶贮藏过程中品质变化规律

为了探明不同茶树品种制绿茶在常温贮藏期间的品质变化规律,以保靖黄金茶1号、保靖黄金茶2号和福鼎大白茶3个茶树品种制成炒青绿茶为材料,密封贮藏于避光室温环境中,分析不同贮藏时间对其品质的影响。结果表明,保靖黄金茶1号、保靖黄金茶2号和福鼎大白茶制绿茶贮藏过程中茶多酚含量（降幅分别为13.96%、15.86%和26.29%）和水浸出物含量（降幅分别为9.81%、10.00%和16.28%）均显著降低,且前两个月降幅较大;氨基酸含量总体下降（降幅分别为20.87%、23.50%和37.94%）,其中贮藏第四个月出现小幅上升;咖啡碱含量前3个月的下降幅度（降幅分别为7.99%、10.82%和13.84%）较大,此后变化幅度减小;叶绿素含量明显下降（降幅分别为15.92%、17.81%和28.49%）;可溶性总糖含量呈现先高后低的波浪形变化,并且香气、汤色、滋味等感官审评指标也有不同程度的下降。三个品种间比较,保靖黄金茶1号、保靖黄金茶2号所制绿茶在贮藏过程中的主要生化成分下降幅度显著低于福鼎大白茶,表现出较好的化学品质特征。     

抹茶蛋卷贮藏品质与货架期预测模型研究

当前抹茶烘焙食品广受消费者青睐,对抹茶烘焙食品贮藏品质进行研究具有重要的实际应用意义。本文以抹茶蛋卷作为研究对象,采用食品保质期加速测试法,研究其贮藏过程中水分含量、过氧化值、酸价和色差的变化,并基于Arrhenius模型构建抹茶蛋卷的货架期预测模型。结果表明：抹茶蛋卷在贮藏过程中随着时间的延长水分含量、色差L值和b值较为稳定,色差a值呈上升趋势,过氧化值逐渐增加,酸价呈现先增加后减少的趋势。以色差a值作为主要品质劣变指标,进行零级反应动力学方程拟合,建立抹茶蛋卷货架期预测模型,25℃条件下预测货架期为325.39 d。     

普洱茶贮藏过程中主要化学成分含量及感官品质变化的研究

将成品普洱茶在不同条件下贮藏,分析其茶多酚、可溶性糖和氨基酸含量的变化和感官品质的变化,结果表明:贮藏时茶叶含水量和周围环境温度升高,最佳品质出现时间提前,55℃/12%的处理最佳品质出现在贮藏45天左右,37℃/9%的处理最佳品质出现在贮藏135天左右,处理后感官品质明显优于对照。茶多酚、可溶性糖随着贮藏时间延长、贮藏温度提高而下降,且茶叶含水量高者下降幅度大。氨基酸随着贮藏时间延长、贮藏温度提高而下降,但与茶叶含水量相关性不大。     

青梅腌制过程中的风味物质变化

以腌制青梅果肉为样品,采用顶空固相微萃取-气相色谱-质谱联用技术（HS-SPME-GC-MS）对青梅腌制过程中的风味成分分析鉴定,并进行统计分析。结果表明：其中,醛类物质14种、醇类9种、酯类7种、酸类3种、酮类3种、烷烃类12种和其他杂环类2种（占总挥发性的84.52％）,共检测出50种挥发性成分。在腌制过程中,醛类和烷烃类与腌制时间显著负相关(p<0.01),醇类风味物质含量与腌制时间呈弱负相关(p<0.05),酯类物质含量与腌制时间显著正相关(p<0.01)。典型风味成分苯甲醛含量高达19.80％,腌制第2天,果肉中风味成分含量高且丰富,当腌制第8天时,风味成分变化趋于稳定。     

不同品种类型玉米口感与营养及风味品质的比较

以糯玉米、普通玉米、甜玉米为材料,研究其口感与营养及风味品质的相关性.结果表明:感官品尝是研究玉米食用品质的有效手段;糯玉米各类营养物质含量较高且均衡,较好地解决了甜、糯、韧、滑的口感问题,其次为甜玉米,普通玉米最差;胚乳中的含糖量和支链淀粉含量与口感有密切关系;糯玉米风味品质以脂香和蜡香为主,主要成分包括棕榈酸、亚油酸、正十六羧酸乙酯等.     

Effect of microwave pre-treatment on physical quality,bioactive compounds,safety risk factor,and storage stability of peanut butter

Microwave, as a new heat treatment technology, has the characteristics of uniform and fast heating speed. It is an energy-saving technology known for improving oilseed product quality. Its efficiency mainly depends on the roasting power and time. However, the production of high-quality peanut butter using short-time roasting conditions are limited. Herein, we determined an appropriate microwave roasting power and time for peanuts and evaluated its impacts on the quality of peanut butter. Different roasting powers (400 ​W, 800 ​W and 1200 ​W) and times (4, 4.5, 5, and 5.5 ​min) were preliminarily tested. Among them, 800 ​W at 5 ​min was the most suitable. The roasting efficiency was further evaluated using color, sensory, bioactive compounds, storage stability, and safety risk factors of peanut butter produced from four peanut cultivars (Silihong, Baisha-1016, Yuanza-9102, and Yuhua-9414). The pre-treated butter obtained from three cultivars (Silihong, Yuanza-9102, and Yuhua-9414) with moisture content between 5% and 7.2% had a similar sensory score (6–7) as the commercial on a 9-point hedonic scale compare to the other. The color of the pre-treated peanut butter varies statistically with the commercial but remained in the recommended range of Hunter L1 values of 51–52, respectively, for high initial moisture peanut cultivars. The total polyphenol (35.20-31.59 ​± ​0.59 ​μmol GAE/g) and tocopherol (19.05 ​± ​0.35 ​mg/100 ​g) content in the butter obtained from three cultivars (Yuahua-9102, Yuhua, and Baisha-1016) and Silihong respectively, were significantly (P ​< ​0.05) higher than those in the commercial butter. The induction times of all pre-treated butter (19.80 ​± ​0.99–7.84 ​± ​0.07 ​h) were significantly (P ​< ​0.05) longer during storage at accelerated temperature than commercial samples. In addition, no benzo[a]pyrene was found in the pre-treated samples. Collectively, the microwave pretreated peanut butter was superior to the commercial one. These findings provided data support and a reference basis to promote microwave use for peanut butter production.     

Evaluation of partial-vacuum baking for gluten-free bread: Effects on quality attributes and storage properties

The purpose of this study was to evaluate the impact of partial-vacuum baking on the quality and storage properties of gluten-free bread (GFB). Conventional (180°C-30 min at atmospheric pressure) and partial-vacuum (180°C-15 min at atmospheric pressure and at 180°C-15 min at 60 kPa vacuum pressure) methods were conducted to bake GFB. Quality attributes (specific volume, colour, texture, total water loss) were assessed, DSC and SEM analyses were carried out to understand the effect on the bread's microstructure when using vacuum during baking. No significant differences (p > 0.05) were observed in the hardness and specific volume of the partial-vacuum baked GFB; however, changes in the total water loss and in the total colour change were statistically significant (p < 0.05). The DSC, SEM and XRD results showed that more crystalline structure and different starch crystal types formed after partial-vacuum baking. Storage properties were also investigated over a 3-day period. Partial-vacuum baking significantly affected the total water loss and the texture parameters (p < 0.05) during storage. Partial-vacuum baked samples were softer and had a tendency to become stale more slowly than the control. The findings indicate that the partial-vacuum baking method increases the shelf life of gluten-free products by modifying the microstructure of the bread.     

膨爆预处理对三种菜籽油品质及挥发性风味成分的影响

本文以甘蓝型、白菜型和芥菜型三种油菜籽为原料,探究了油菜籽经过膨爆预处理后菜籽油的品质及挥发性风味成分的变化。研究结果表明,膨爆预处理后甘蓝型、白菜型和芥菜型三种菜籽油的酸值和过氧化值均显著增加（P＜0.05）,分别增加了0.25、0.49、0.39 mg KOH/g和0.20、0.18、0.18 mmol/kg,均在国际食品法典规定的范围内;三种菜籽油的氧化诱导时间均显著增加（P＜0.05）,分别增加了17.32、10.06和13.99 h。膨爆预处理对三种菜籽油的脂肪酸组成无显著影响。膨爆预处理后,甘蓝型、白菜型和芥菜型三种菜籽油中苯乙腈、3-甲基巴豆腈、5-己烯腈等含硫化合物含量、杂环类物质以及氧化挥发物的种类和含量均显著增加（P＜0.05）,杂环类物质和氧化挥发物中分别是以吡嗪类和醛类物质为主。     

不同种类有机肥与钼肥配施对连作花生生长发育及产量、品质的影响

采用大田试验,研究增施有机肥和钼肥对连作花生生长发育及产量和品质的影响。结果表明,在合理施用氮磷钾肥基础上,增施有机肥和钼肥可以明显促进花生的生长发育和根瘤的形成,提高产量,改善品质性状。增施钼肥花生单株根瘤数增加4.8～9.5个,侧枝长和单株有效分枝数分别增加1.4～10.3cm、1.2～2.5条,产量提高6.3%～22.3%,植株钼积累量提高1.72～2.69倍。增施有机肥花生产量提高8.2%～15.0%,蛋白质和粗脂肪分别增加13.2%～27.9%和10.3%～20.4%,但不同有机肥间效果差异不显著。本试验最佳组合为：每公顷施饼肥1200 kg+钼肥播种。      

Hard-to-cook phenomenon in chickpeas (Cicer arietinum L): Effect of accelerated storage on quality

Storage, at high temperature ( 25^°C) andhigh relative humidity ( 65%), causesdevelopment of hard to cook (HTC) phenomenon in grainlegumes. The objective of this work was to study theeffect of storage simulating tropical conditions onchickpeas quality. The hardening of the Surutato 77,Mocorito 88, and Blanco Sinaloa 92 chickpea varietieswas produced using adverse storage (32 ± 1^°C, RH = 75%, 160 days) conditions. For all samples, theHunter `L' values decreased and E valuesincreased during storage, meaning a loss of colorlightness and development of darkening. Acceleratedstorage caused a significant decrease in the waterabsorption capacities and cooking times of whole seeds,cotyledons and seed coats of all samples, being morepronounced in The Blanco Sinaloa 92 variety. Furthermore,storage produced significant decreases in the seedcoat tannin content of the three materials; thisparameter increased significantly in the cotyledon. Inall samples, the levels of phytic acid decreasedsignificantly with the seed hardness. Hardening ofchickpea grains caused a decrease in the invitro protein digestibilities of all varieties. Theseresults suggest that both thecotyledon and seed coat play a significant role in theprocess of chickpea hardening. Blanco Sinaloa 92 andMocorito 88 might be classified as varieties with highand low proneness, respectively, to the development ofthe HTC condition.     

硒对花生抗氧化作用的初步研究

通过对花生叶面喷施不同浓度的亚硒酸钠，初步研究了硒对花生抗氧化作用的影响，结果表明，10～60mg/LSe使叶绿素的含量和POD活性高于对照，且随着硒浓度的增加，它们的含量也相应增加;而MDA低于对照，随着硒用量的增加而下降。在Se浓度达到90 mg/L时，叶绿素含量、POD活性呈下降趋势而MDA含量则升高。10～90mg/LSe使CAT和SOD低于对照，先随硒浓度的增加而下降，在高浓度硒时又上升。     

稻谷储藏时间对稻米品质影响的研究

2000年对储藏了3.5年的陈种与0.5年的新种稻谷米质变化进行了研究。结果表明，11个灿稻品种的陈种，其表观直链淀粉含量、热水不溶性直链淀粉含量基本稳定，但其粘滞性淀粉谱发生了显著变化；所有11个品种的起浆温度从平均的75.8℃增高到84.7℃，增幅为4.0-15.1℃；有10个品种的峰值粘度和崩解值下降，1个品种上升；热浆粘度、冷胶粘度和消碱值有升有降，品种之间存在差异。     

Effect of hydrostatic high pressure pretreatment on flavor volatile profile of cooked rice

The impact of high hydrostatic-pressure (HHP) processing on the volatile profile of cooked Japonica rice (Wuchang) and Jasmine rice (Complete Wheel) was investigated by SPME–GC/MS. Presoaked samples were treated at 200, 400 and 600 MPa for 10 min and then cooked for volatile compound analysis. Seventy-seven compounds were identified in two cooked rice varieties: 20 aldehydes, 16 alcohols, 14 ketones, 9 arenes, 7 esters, 5 alkanes, 3 olefins and 3 hetero-cycle compounds. Results showed that both pressure level (P < 0.01) and rice variety (0.01 < P < 0.05) significantly impact the volatile compounds in rice and there is also an interaction between pressure and rice variety (P < 0.01). Overall, HPP decreased the amount of aldehydes more obviously in Complete Wheel rice than that in Wuchang variety. Both 200 and 400 MPa increased the levels of alcohols, ketones, esters and olefins, but reduced those of heterocycles, alkanes and arenes. Similar volatile change trends were found at 600 MPa except the concentration of each component was closer to that of control group. Based on the changes in the three key flavor compounds in rice (aldehydes, alcohols and ketones), the HPP process could be a suitable alternative to traditional pretreatment for improving flavor in cooked rice.     

花生苗期不同程度干旱胁迫 对叶片某些酶活性的影响

在人工控水条件下,研究了花生苗期不同程度干旱胁迫对叶片某些酶活性的影响,结果表明:随着干旱 程度的增加,花生叶片光合速率逐渐下降,叶中丙二醛(MDA)含量增加;适当干旱(灌水60～80mm) ,可增加叶片 中超氧化物歧化酶( SOD) 、过氧化物酶( POD) 、过氧化氢酶(CAT)的活性,提高叶片可溶性蛋白质( Pr)含量;充分 灌水后,叶中SOD、POD、CAT活性和Pr、MDA含量显著降低,而光合速率显著升高。要保持花生叶片较好的生理特 性,苗期灌水量不能低于60～80mm。