MEASUREMENT OF CHLOROGENIC ACID AND FLAVONOL GLYCOSIDES IN APPLE JUICE BY A CHROMATOGRAPHIC-FLUOROMETRIC METHOD

Methods are described that measure chlorogenic acid at concentrations as low as 1 mg/100 ml of juice and flavonol glycosides at levels as low as 0.2 mg/100 ml of juice. Results are given for several apple juices, indicating concentrations of chlorogenic acid ranging from 12–31 mg/100 ml juice. Flavonol glycosides in conventional juices were 0.4–0.7 mg/100 ml, while special juices had 6.5–8.5 mg/100 ml     

纳他霉素在草莓防腐中的应用

研究了导致草莓腐败的主要病菌,用目前国内批准使用的2种天然防腐剂之一的纳他霉素对草莓防腐。结果表明,根霉、黑霉是导致草莓变质的主要病菌,用浓度为500mg/L的纳他霉素悬浮液喷洒的草莓,在温度为18℃～22℃,湿度为58%～65%条件下放置10d后腐败率仅为10%,而且纳他霉素还能使草莓具有甜中带酸的优良品质。     

草莓粉非酶褐变的抑制及抗结块性研究

对草莓粉非酶褐变的抑制及抗结块性进行了研究,结果表明：添加适量的亚硫酸氢钠、采用内置干燥剂的阻湿阻氧好的保鲜袋包装、在低温低湿条件下贮藏,对草莓粉非酶褐变具有很好的抑制作用;添加硬脂酸镁1.0%、微晶纤维素0.5%、硅胶0.5%,对草莓粉具有很好的抗结块作用.     

FACTORS INFLUENCING THE BREAKDOWN OF FRUIT IN STRAWBERRY JAM

Abstract. Structural changes produced in strawberries when made into jam were studied by light microscopy. The results indicated that only the epidermal and vascular tissues retained their structural integrity, whereas the bulk of the cells were collapsed and in some instances ruptured. The extent to which fruit of different cultivars broke down during the jam making process was determined, and an expression representing fruit wholeness was derived. It is concluded that a relationship exists between the extent to which strawberries disintegrate during jam boiling and the density of achenes on the surface of berries of a given size.     

蓝莓果实中花色苷提取工艺的研究

以人工栽培蓝莓果为原料,进行了蓝莓花色苷提取工艺的研究.结果显示,蓝莓花色苷最佳提取工艺为:采用15倍量、浓度为80%的酸性甲醇(pH为2),40℃提取2次,每次提取1 h.蓝莓花色苷提取率为78.2%.     

玉米醇溶蛋白复合膜在草莓保鲜中的应用研究

玉米醇溶蛋白有极强的疏水性和良好的成膜性,可用做果蔬等农产品的保鲜膜,绿色无毒.采用正交试验方法筛选最佳涂被剂配方的结果表明,玉米醇溶蛋白为2.5%,甘油0.10%,柠檬酸0.15%,浸泡时间1min,保鲜效果最佳.     

固定化乳酸菌发酵草莓酸奶工艺研究

研究用海藻酸钠包埋乳酸菌发酵草莓酸奶工艺.研究结果表明固定化乳酸菌发酵草莓酸奶的最佳工艺条件为:海藻酸钠溶液浓度为1.5%,含菌种脱脂乳用量为6mL/100mL海藻酸钠溶液,胶珠的添加量为100mL海藻酸钠溶液/100 mL草莓奶液,胶珠直径为2 mm～3 mm,培养温度为40℃,白砂糖添加量为10%,草莓浆添加量15%.连续发酵结果表明固定化乳酸菌发酵草莓酸奶可连续使用10次.     

不同处理措施对草莓汁加工过程中Vc保存率的影响

以新鲜草莓果实为原料，对草莓汁加工过程中的Vc含量变化及其控制方法进行了研究。结果表明，快速清洗有利于草莓果中Vc的保存；微波热烫较热水热烫的Vc保存率高；热压榨方式有利于保持草莓的Vc含量；草莓汁灭菌时采用90℃灭菌15min的效果最好，灭菌后快速冷却有利于草莓汁中的Vc保存。     

草莓色素稳定性研究

通过对不同条件下草莓色素特征吸光值变化的研究,探讨其在不同温度、pH、光照、氧化剂、还原剂、食品添加剂、金属离子等环境下的稳定性.试验结果表明,色素在pH值1～4,温度60℃以内比较稳定;光照能加快色素降解;Na+、Ca2+、Mg2+对色素有一定的增色护色作用;Fe3+、Al3+、Cu2+对其有不良影响;Vc、NaSO3对色素有严重的破坏作用,食品添加剂对色素无影响.因此,草莓色素作为食用色素具有很好的开发价值.     

树脂法提取纯化草莓色素的研究

研究以草莓为原料、用大孔树脂提取和纯化草莓色素的工艺条件.试验结果表明,最佳的工艺条件是:提取液为0.1 mol/L的盐酸溶液;最佳树脂是AB-8树脂;最佳吸附条件是:50℃,pH=1.5的条件下吸附,吸附流速为1 BV/h;最佳解吸条件是:用pH=1.5时,50%的乙醇在室温条件下洗脱,洗脱流速为0.5 BV/h.     

IDENTIFICATION OF SENSORY COLOR OPTIMA OF STRAWBERRY YOGURT

Commercially available strawberry yogurts were subjected to preference ranking done by an untrained panel and to instrumental color analysis. Spectral reflectance data and color values expressed in the CIELAB system revealed different color properties of the yogurts, mainly with respect to the hue angle determining whether a product is, e.g., dominantly red or dominantly orange. Sensory evaluations resulted in three groups of products being significantly different from each other with respect to their preference patterns. The tomato color index originally proposed for measuring the ripening index of tomatoes appeared to be useful to reduce 3‐dimensional yogurt color values to one dimension and to construct a function of preference ranks versus instrumentally measured data.     

草莓汁加工贮藏过程中维生素C稳定性的研究

初步考察了影响草莓汁加工贮藏过程中维生素C变化的因素。采用正交试验法,以加工贮藏过程中维生素C的保存率为考察指标,对维生素C的变化进行了初步研究。结果表明,实验设计的三因素中含空气量对维生素C的变化有显著影响。最佳加工贮藏初步工艺为:采用热榨加工工艺,在15-18℃冷室,无氧贮藏方式。为草莓汁的进一步加工贮藏提供了理论依据。     

几种不同化学保鲜剂对草莓贮藏保鲜效果的对比研究

比较了过氧乙酸、过氧乙酸＋氯化钙、氯化钙3种保鲜剞对草莓贮藏保鲜效果的差异，结果表明过氧乙酸保鲜效果最好，其次是过氧乙酸＋氯化钙，氯化钙处理保鲜效果最差。过氧乙酸的浓度以0．01％最好，氯化钙的浓度为4％最好。     

壳聚糖-有机酸复合物常温下对草莓保鲜的作用研究

壳聚糖在一定条件下与有机酸生成具有一定粘度的壳聚糖-有机酸复合物,在常温下将其涂膜新鲜草莓后,果实表面形成一层光滑、透明的可食用膜,能有效降低草莓的失水率、延缓草莓衰老过程,同时,还能减少草莓腐烂率,通过实验得出结论：经1.25%酒石酸配制1.25%壳聚糖涂膜液处理后的草莓在常温（22～24℃）下贮藏2 d后,果实品质与鲜果几乎无差别;贮藏5 d后,好果率仍达到80.2%.