Carotenoid and flavanone content during refrigerated storage of orange juice processed by high-pressure, pulsed electric fields and low pasteurization

The impact of different processing technologies, including non-thermal technologies, on bioactive compounds of orange juice was investigated. Freshly squeezed orange juice was treated by high pressure (HP) (400 MPa/40 °C/1 min), pulsed electric fields (PEF) (35 kV cm⁻¹/750 μs) and low pasteurization (LPT) (70 °C/30 s). The stability of main carotenoids and flavanones was studied just after treatment and during 40 days of refrigerated storage at 4 °C. Just after treatment, HP juice showed a significant increase on total carotenoid and flavanone content extracted (45.19 and 15.46%, respectively) and on vitamin A value (30.89%) with regard untreated juice, whereas no significant changes were observed for PEF and LPT juices. For all treated orange juices, flavanone content decreased significantly (around 50%) during the first 20 days of storage at 4 °C while carotenoid content showed a moderate decrease (less than 11%) that took place during the last 20 days. In general, during refrigerated storage, carotenoids and flavanones remained higher in HP juice than in LPT and PEF juices. Hence, HP and PEF technologies were as effective o even more than LPT to preserve bioactive compounds in orange juice during refrigerated storage.     

惰性粒子流化床蒸发器浓缩南瓜汁的传热研究

根据惰性粒子流化床蒸发器的结构特点,将其用于浓缩南瓜汁,讨论了惰性粒子在流体中的运动情况及其对循环流化床蒸发器浓缩南瓜汁的传热性能的影响,建立了汽-液-固三相流动沸腾传热准数经验关联式.实验结果表明,该准数经验关联式的计算值与实验值吻合较好.     

高澄清度桑椹果汁饮料加工工艺研究

详细介绍了高澄清度桑椹果汁饮料的加工工艺及关键技术,确定了产品的配方和最佳工艺参数.研究表明:采用-23℃低温速冻,40～50℃温水快速解冻,然后榨汁,再用果胶酶-明胶法澄清,可得高澄清度的桑椹果汁;产品的最佳配方为:桑椹原汁50%、糖酸比25:1、蔗糖用量9%.     

Comparative evaluation of the quality of red globe grape juice fermented by Lactobacillus acidophilus and Lactobacillus plantarum

Basic analysis, electronic senses and HS-SPME/GC-MS were used to evaluate the effects of single and mixed cultures of Lactobacillus acidophilus-26 and Lactobacillus plantarum-56 on the quality of fermented red globe grape (RGG) juice. The results showed that mixed culture fermentation was superior to single strain fermentation in terms of viable bacteria counts, consumption of total sugar (TS), total soluble solids, pH, functionality, and antioxidant properties of RGG juice (RGGJ). Whereas the aroma profiles of developing juices were dominated by abundant esters, acids, alcohols, aldehydes, and ketones. Compared with the single inoculation, co-inoculation of the two species induced lactic acid fermentations, leading to accumulation of acetic acid, ethyl acetate, and 2-hexenol significantly. Moreover, higher concentrations of ethyl acetate, benzoic acid ethyl ester, octanoic acid, sorbic acid, 2-phenylethanol, and 2-hexenol represented the characteristic flavours of juices. To sum up, these findings suggested that L. acidophilus-26 and L. plantarum-56 could be used as fermented strains to ferment and improve the quality of RGGJ.     

苹果浊汁加工中果实成熟度的选择

以生理成熟和完全成熟 2种成熟度的苹果为原料制取浊汁 ,对苹果汁的褐变情况、苹果汁PPO酶的热失活条件、浊汁理化性状以及悬浮稳定性进行比较 ,试验结果表明 :完全成熟的苹果更适宜用作制取浊汁的原料。文中还就苹果果肉细胞的微观形态、影响悬浮稳定性的因素进行了探讨 ,以深入探究完全成熟的苹果更加适宜制取浊汁的机理。     

取汁方式对热破碎番茄汁品质的影响

研究了2种取汁方式在不同的热处理条件下对热破碎番茄汁品质的影响。结果表明,破碎-加热-打浆取汁方式(简称为BHJ)的番茄汁粘度、果胶含量和番茄红素含量显著高于打浆取汁-加热的取汁方式(简称为JH),但取汁方式对汁的色差影响不大。在本试验范围内,BHJ取汁的番茄汁品质优于JH取汁。     

钠盐对果汁豆奶稳定性的影响

采用单因素实验及正交实验分别研究了单个磷酸盐、柠檬酸盐及复合磷酸盐等含钠离子的不同盐类豆奶稳定性的影响。结果表明,钠类盐的加入能使体系的粘度及稳定性升高,但其添加量有最佳值,此值因盐的种类不同而不同;柠檬酸三钠的稳定效果优于单个的磷酸盐,但不如复配磷酸盐。加入柠檬酸三钠和复合磷酸盐后,果汁豆奶中的平均粒径均表现出增大的趋势。     

金丝枣汁苹果醋复合饮料研制

以苹果和金丝枣为原料,酵母菌、醋酸菌作为发酵菌种,以摇瓶发酵法制备的苹果醋与酶解法制备的枣汁进行调配制成复合饮料。在单因素试验的基础上,通过正交试验确定最佳配方,结果表明：苹果醋添加量61%、金丝枣汁添加量23%,果葡糖浆添加量16%。     

狼尾草复合酶酶解参数优选研究

研究果胶酶和纤维素酶复合酶解狼尾草对出汁率的影响效果。通过果胶酶用量、纤维素酶用量以及时间三因素的单因素试验。在单因素试验基础上,运用二次旋转组合设计正交,选取纤维素酶、果胶酶和时间为实验因素,确定复合酶酶解提高狼尾草出汁率的最佳工艺参数。实验结果表明,在45℃时,纤维素酶用量1.14%,果胶酶用量0.6%,时间4.5 h达到最大值86.11%。