奉节脐橙果实留树和低温保鲜期间滋味品质变化分析及综合评价

探究奉节脐橙在不同保鲜方式贮藏期间主要滋味物质的变化,以及不同处理对脐橙果实贮藏期间滋味品质影响的综合评价方法。以奉节脐橙为试验材料,采用3种不同类型的保鲜方式(留树保鲜、混合保鲜剂+低温和2%壳聚糖+低温),研究贮藏过程中基本生理指标、可溶性糖、有机酸和柠檬苦素的变化,利用因子分析建立滋味品质综合评价体系。结果表明,3种保鲜方式均可有效减缓贮藏保鲜过程中脐橙果实维生素C、可溶性固形物和可溶性糖的降解,并显著抑制了有机酸和柠檬苦素的上升,这表明3种保鲜方式都能在一定程度内维持贮藏期间脐橙果实的滋味品质。通过综合评价体系可知,留树保鲜的方式最优,且留树保鲜30 d和75 d为留树保鲜脐橙果实的最佳采收时期。该研究为今后脐橙果实保鲜方式的选择及贮藏过程中滋味品质的相关变化提供科学依据。     

山野菜保鲜贮藏基础知识讲座

<正> 三、山野菜化学成分与保鲜贮藏 山野菜中化学成分的含量和组成比例,直接决定着山野菜的营养价值和风味特点。山野菜在采收、运输、贮藏、加工等过程中,这些化学成分常常发生不同的变化,从而影响山野菜的品质和营养价值。山野菜保鲜贮藏的主要目的在于防止腐败变质,并保持其营养与风味,实质上就是控制山野菜化学成分的变化。了解掌握这些变化,可在保鲜贮藏过程中创造适宜的条件,以减少营养物质的破坏,提高山野菜的营养价值与鲜嫩品质,符合食用要求。下面介绍山野菜化学成分特征。     

草莓贮藏保鲜方法的研究进展

论述了草莓贮藏保鲜的基本条件,包括采收、温度和湿度;草莓贮藏保鲜的物理方法、化学方法和天然生物保鲜方法等;并指出了今后草莓贮藏保鲜技术的发展趋势。     

采收成熟度、温度,气体成分对青州蜜桃保鲜效果的影响

青州蜜桃采后呼吸和乙烯释放都呈明显的双峰变化规律。进行长期贮藏的果实须在第一峰出现之前采收,果实对乙烯非常敏感,贮藏过程须加以排除。在研究采后贮藏生理的基础上,经试验提出了冷藏和MA气调贮藏保鲜组合技术,使青州蜜桃贮藏保鲜寿命达到130d以上,好果率90%以上,较好地保持了果实品质。     

真空预冷及贮藏方式对生菜品质的影响

为了提高生菜的真空预冷及保鲜效果,采用不预冷+25℃贮藏、不预冷+6℃贮藏、真空喷水预冷+6℃贮藏以及真空喷CaCl2溶液+6℃贮藏4种方式,从感官品质、失重率、叶绿素含量及维生素C含量四个方面研究了不同预冷和贮藏方式对采后新鲜生菜品质的影响。结果表明:生菜采收后,感官品质、叶绿素和维生素C含量均随贮藏时间的延长而下降,失重率上升。真空预冷前喷洒0.5%浓度的CaCl2溶液+6℃贮藏的方法既能补充真空预冷过程中的水分损失,又能延长生菜的贮藏期,减缓生菜的失重率增长、叶绿素和维生素C含量的降低,是一种能将快速预冷和保鲜贮藏结合起来,且省时有效的好方法,为探寻预冷保鲜的新途径提供了理论依据。     

草莓贮藏保鲜方法的研究进展

论述了草莓贮藏保鲜的基本条件，包括采收、温度和湿度；草莓贮藏保鲜的物理方法、化学方法和天然生物保鲜方法等；并指出了今后草莓贮藏保鲜技术的发展趋势。     

甘薯气调保鲜最佳贮藏条件研究

将气调保鲜技术应用于甘薯的贮藏,研究不同的气调贮藏条件对甘薯保鲜效果的影响,筛选最佳气调贮藏条件,并将保鲜效果同普通冷藏对照组比较。结果表明:采用温度12℃,CO25.0%,O28.0%,相对湿度90%的气调贮藏条件,保鲜效果比普通冷藏对照组明显更好。气调贮藏150 d,感官新鲜饱满,不生根萌芽、不软腐、不糠心,好薯率提高15.8个百分点,失重率减少4.9个百分点,VC和β-胡萝卜素保存率分别提高24.8和21.8个百分点,呼吸曲线明显下移,刚入贮时提早5 d进入呼吸平稳期,所有呼吸强度值减少40%以上。     

竹笋采后生理生化变化及贮藏保鲜研究进展

竹笋作为一种高纤维、高蛋白、低脂肪、低糖的绿色森林蔬菜,越来越受大众喜爱。但是竹笋的采收季节集中,采后代谢旺盛,在运输和贮藏的过程中极易腐烂老化,由此导致竹笋的营养价值和商业价值大大降低。本文首先介绍我国可食用竹笋口感、形态、产地、采收期,然后从采后竹笋的外观品质、呼吸作用、蒸腾作用、木质化等方面阐述竹笋采后生理生化变化,并详细综述国内外不同保鲜方法（传统保鲜、物理保鲜、化学保鲜和生物保鲜）在竹笋贮藏保鲜上的应用,以期为基于竹笋采后生理生化变化开发新型贮藏保鲜技术提供参考。     

龙薯九号甘薯冷害胁迫与适温贮藏品质调控

针对温度敏感性甘薯低温贮藏冷害、高温腐烂率加剧损耗大等产业难题,试验以"龙薯九号"新鲜甘薯为试材,重点研究0℃强冷害、14℃适宜贮温和25℃偏高温度品质变化规律。结果表明,14℃对甘薯的贮藏效果最佳,显著延缓失重率的降低,抑制电导率和丙二醛含量的增加,同时抑制多酚氧化酶(PPO)和过氧化物酶(POD)的活性,延缓甘薯衰老褐变;0℃贮藏甘薯冷害严重,薯块色泽黯淡,薯肉变褐色,木质化现象明显,细胞损伤严重,导致甘薯品质下降;25℃时,甘薯呼吸强度大,失重率急剧上升,果实衰老快,品质差。试验为龙薯九号甘薯新品种贮藏保鲜提供了理论依据。     

采收成熟度和时间菜豆采后贮藏品质的影响

以贵阳青棒豆为试材,研究了不同采收成熟度和时间采收菜豆贮藏期间主要理化指标变化规律的影响。研究显示:不同采收成熟度和时间对菜豆采后保鲜效果影响显著,其中,六成熟时采摘豆荚期间品质变化较缓和,贮藏24 d营养成分损失较小,豆荚纤维化、黄化不明显,消费者易接受;5月中旬采收菜豆的贮藏品质显著高于其他几个采收期,有利于贮运。因此,贵阳青棒豆大棚栽培以4⁵月份气候条件最佳,六成熟时采摘。     

不同熟化方式对速冻熟紫薯品质的影响

为深入研究冻前不同熟化方式对速冻熟紫薯品质的影响,本实验以‘紫罗兰’紫薯为原料,采用蒸制、微波制和烤制3种熟化方式处理速冻熟紫薯,并对挥发性成分、色泽、微观结构、花色苷含量和抗氧化活性等进行分析。结果表明,不同熟化方式能够引起速冻熟紫薯中挥发性风味物质的重新分布,提供更多的芳香气味和独特的风味。熟化处理使速冻熟紫薯内组织结构发生变化,使其更易于消化,同时不同熟化处理紫薯花色苷含量也有显著差异,其中蒸制熟紫薯达4.12 mg/g,与鲜紫薯（3.36 mg/g）相比显著提高（P<0.05）。经液相色谱串联质谱（liquid chromatography tandem mass spectrometry,LC-MS/MS）分析鉴定出的紫薯花色苷共有六大类,主要是芍药色素和矢车菊素,蒸制熟紫薯中芍药花素占比最大,达到总量的84.12%,较好地保留了紫薯营养成分和色泽。此外,熟化处理还提高了速冻熟紫薯中花色苷在胃肠消化过程中的释放量,进而显著提高了其抗氧化活性（1,1-二苯基-2-三硝基苯肼自由基清除率、2,2-联氮基双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除率和O2-·清除率）,...     

添加剂对熟制甘薯抗老化作用的研究

为了抑制熟制甘薯在贮藏期间的老化,以优质甘薯为原料,经烘烤、熟刺、搅拌成泥,加入抗老化剂制成熟制甘薯食品,并进行冷冻储藏。研究了添加不同抗老化剂对熟制甘薯的保水力、糊化性质和老化程度的影响。结果表明,添加了抗老化剂的熟制甘薯保持了其特有的口感风味,且保水力较大,糊化特性和老化度都不同程度地优于不添加抗老化剂的熟制甘薯．     

Microbiological quality of fresh-cut sweet potatoes

Sweet potato roots were dipped in various concentrations of chlorine for 5 min at 1 or 20 °C before and after slicing, and then stored at 2 or 8 °C for 14 days to evaluate the effects of different chlorine treatments and storage temperatures on the microbiological quality of fresh‐cut sweet potato slices. The microflora of fresh‐cut sweet potato slices was dominated by mesophiles, followed by psychrotrophs and fungi initially and during storage. The 2 °C storage was necessary to keep the microbial load at a low level. No spoilage was observed in fresh‐cut sweet potatoes at both storage temperatures for 14 days. Chlorination of sweet potatoes before slicing was not effective in ensuring acceptable microbiological quality of fresh‐cut sweet potatoes. Dipping slices in 200 ppm chlorine at 1 °C reduced the population of all micro‐organisms during storage.     

不同贮藏方式对土豆中VC含量的影响

以探讨不同贮藏方式对土豆中VC含量的影响为目的;采用2,6-二氯靛酚滴定法测定不同贮藏方式下的土豆中VC的含量变化;结果是三种贮藏方式下的土豆中VC的含量随着贮藏时间增加而降低,常温贮藏比低温贮藏的土豆VC含量和保存率较高,连续干燥比间歇干燥时维生素保存率高。     

甘薯全粉加工关键技术研究进展

甘薯全粉是新鲜甘薯经脱水干制、粉碎等工艺加工而成的粉状散粒体,它最大限度地保持了新鲜甘薯的营养价值和风味,市场前景广阔。文中对甘薯全粉的生产工艺进行了综述,并重点阐述了去皮、护色、降低淀粉游离率和干燥等关键技术的国内外研究进展,以期推动甘薯全粉加工业的进一步发展。     

Effects of combined radio frequency with hot water blanching on enzyme inactivation,color and texture of sweet potato

Sweet potato is an important food crop with rich nutritional value, and also a commonly used feed and industrial raw material. However, the quality of sweet potatoes may decline during storage and thermal processes because of enzymatic reaction induced by peroxidase (POD). Radio frequency (RF) blanching was thus proposed to reduce POD activities. Effects of electrode gaps and sample thicknesses on the RF heating rate and uniformity in sweet potato were studied. Influences of hot water blanching and combination of RF heating with hot water blanching on enzyme inactivation and physiochemical properties of sweet potatoes were also analyzed. Results showed that the optimum RF heating uniformity was obtained at an electrode gap of 90 mm and a sample thickness of 60 mm. Combined RF with hot water blanching effectively inactivated POD in sweet potatoes. Compared to hot water blanching, combined RF with hot water blanching gave better sample color, texture values, and lower weight loss when achieving the same level of enzyme inactivation (< 10%). Therefore, combined RF with hot water blanching is recommended as an effective, uniform and high-quality blanching technology for sweet potatoes.     

Improved Aseptically Filled Sweet Potato Purees

A high quality sweet potato puree with better color stability than frozen purees was produced by flash sterilization followed by aseptic packaging. Starch conversion time was shortened by slicing the sweet potatoes and accurately controlling the temperature during conversion. Processing of inoculated purees for 13 sec at 138°C followed by aseptic filling was adequate for commercial stability. The effect of several processing variables on puree and sweet potato souffle quality was examined. Improved quality and storage stability of sweet potato purees were accomplished by flash sterilization at very high temperatures followed by aseptic packaging.     

PRODUCTION AND PROXIMATE COMPOSITION OF A HYDROPONIC SWEET POTATO FLOUR DURING EXTENDED STORAGE

In developing countries, where limited transport infrastructure exists, processing the sweet potato (Ipomoea batatas (L.) Lam) into flour provides an alternative to the difficulties associated with storage and transport of the raw roots. The objectives of this study were: (1) to process hydroponic sweet potato roots into flour; and (2) to evaluate the nutritive composition and the color of the processed hydroponic sweet potato flour during storage. The TU–82–155 hydroponic sweet potatoes were processed into flour and stored for five months at room and refrigerated temperatures. The sweet potato flour contained 3.0%, 4.5%, 1.0%, 1.0%, 90.6% moisture, ash, fat, protein, and carbohydrate, respectively, with no significant changes during storage. The *L values for the sweet potato flour increased as storage time increased, but the *a and *b values decreased. Hydroponic sweet potato roots could be processed into flour and stored at 4C or 21C to 25C for five months without deterioration in quality.     

甘薯泥作为吞咽障碍食品的研究进展

质构改良食品作为吞咽障碍患者的安全食品,具有质地柔软、吞咽安全及满足患者营养需求的特点,不同国家对吞咽障碍食品的分级各不相同,大多都聚焦于食品本身的质构特性。近些年,吞咽障碍患者的饮食安全备受关注,开发吞咽障碍食品的研究逐渐增加。甘薯泥是新鲜甘薯经过一系列加工制成的泥状食品,保留了甘薯中绝大多数营养物质,具有柔软、营养成分高的特点,是适合吞咽障碍患者食用的质构改良食品的优质原料。但甘薯泥的质构特性受到多方面因素的影响,例如加工原料、加工工艺以及贮藏条件等,限制甘薯泥作为吞咽障碍食品在食品领域的应用。该文将对质构改良食品的分类、甘薯泥加工工艺及影响甘薯泥质构特性的研究进行综述,旨在为适合吞咽障碍患者食用的甘薯泥产品的研发及应用提供理论依据。