Storage of common mushroom under controlled atmospheres

The effect of controlled atmosphere (CA) on the shelf-life of the common mushroom ( Agaricus bisporus ) was assessed using six parameters correlated with its commerical qualities. Low CO₂ concentrations (up to 2.5%) reduced brown discolouration compared to the control in air. Higher CO₂ concentrations enhanced both internal and external browning. Low O₂ concentrations reduced growth of micro-organisms, including pseudomonads. Respiration rate, when the mushrooms are placed again in normal air, is proportional to CO₂ concentration during storage suggesting that CO₂ exhibits a phytotoxic effect on mushrooms. A lower mannitol content was noted in mushrooms stored under CA than those stored in air (control). Mushrooms stored in a 5% CO₂ atmosphere for 7 days did not break their veil but their texture was very soft and spongy. Texture losses decreased when CO₂ concentrations increased.     

加速试验条件下锦橙汁品质劣变关键指标评价

以自制非浓缩还原锦橙汁为原料,利用加速破坏性试验模型,选择导致橙汁品质劣变温度作为加速因子,分别在30℃和40℃条件下进行35d和12d货架期贮藏试验,每隔一定时间对样品进行感官评定和理化检测。结果表明:在30℃和40℃贮藏温度下,随着贮藏时间的增加,非浓缩还原橙汁的抗坏血酸含量显著下降,总色差和褐变指数显著增加,且变化值与感官总体评价变化之间达到了极显著相关(r>0.95),因此可以将抗坏血酸降解率、总色差、褐变指数作为非浓缩还原型锦橙汁贮藏期间品质劣变的关键指标。     

杏鲍菇饼干的生产工艺及货架期预测

以杏鲍菇粉代替部分面粉,探讨杏鲍菇饼干的生产工艺及货架期。选择杏鲍菇粉、糖粉和黄油的添加量以及烘烤时间和烘烤温度为单因素进行梯度实验,通过对产品品质进行评价,确定其最佳工艺参数为:以低筋面粉量为烘焙百分比100%,杏鲍菇粉15%,糖粉35%,黄油70%,全蛋液15%,奶粉5%,烘烤温度为上火190℃,下火为200℃,烘焙18 min;同时应用ASLT法预测杏鲍菇饼干的货架期为109 d。      

真空预冷对芥蓝采后常温货架期品质的影响

以芥蓝(Brassica capitata)为实验材料,研究了采后真空预冷处理对芥蓝冷链物流运输后在常温货架期(25℃)品质的影响。通过测定相关指标,结果表明:采后真空预冷显著地降低了芥蓝在常温货架期间的失重率、黄化指数和相对电导率,延缓了叶片的叶绿素荧光参数(Fv/Fm)、可溶性固形物(TSS)、蛋白及V_C等含量的下降;至常温货架期第3 d,经过预冷的芥蓝,其失重率、黄化指数和相对电导率分别为未预冷的77%、73%和51%,而Fv/Fm、蛋白及V_C含量分别为未预冷的5.5、6.5和1.4倍。说明预冷能够较好地维持芥蓝在常温货架期间的品质。      

复合天然保鲜剂对低温酱鸭保鲜效果的研究

以低温酱鸭为原料，通过对6种天然保鲜剂进行筛选，选出4种抑菌效果较好的，进一步进行组合实验，根据抑菌率得出抑制酱鸭腐败菌的最佳组合为壳聚糖2．00％、乳酸链球菌素（Nisin）0．01％、茶多酚1．00％、桂皮2．40％。采用此最佳组合的复合天然保鲜剂对酱鸭进行保鲜实验，定期测定其微生物指标和理化指标，结果表明利用优选的组合保鲜剂保鲜，加上真空包装、低温水浴杀菌，可使酱鸭保质期冷藏达2-3个月。     

包装方式对双孢菇货架期品质和生理的影响

以双孢菇为对象,研究了不同包装方式对双孢菇货架期品质的影响。结果表明,(4±1)℃销售条件下,与其他包装方式相比,用0.035mmPE抽真空方式进行包装效果显著,能较好地保持双孢菇原有的外观品质,降低了双孢菇贮藏期间PPO活性和MDA浓度,抑制了双孢菇的褐变,延长了双孢菇的货架期时间,与常规PE膜包装相比,延长双孢菇货架期至10d,为双孢菇的销售提供理论依据。     

Genotypic Variations in Quality and Shelf-Life of Fresh Roots of Philippine Sweet Potato Grown in Two Planting Seasons

Sweet potato breeding in the Philippines has recently integrated root quality and shelf-life attributes in varietal development. In this study, the harvest and post-harvest quality of the fleshy roots of different sweet potato genotypes were determined. These genotypes included the existing recommended varieties and the elite selections from the polycross breeding nursery and were grown during the dry and wet planting seasons. Dry matter, starch, sugar and protein contents of freshly harvested roots were found to differ widely with genotype. During storage at ambient temperatures, starch content decreased, sugar content increased and in some genotypes dry matter increased. Protein content of the stored roots varied only slightly from that of fresh roots. The different genotypes also differed in the degree of weight loss, shrivelling, decay and consequently, shelf-life. Some genotypes had short-lived roots (less than 1 month) while others had roots which were still marketable at the end of the 3-month storage period. Root quality and shelf-life similarly varied with planting season. Some genotypes had increased dry matter, starch and sugar contents and long shelf-life when planted in the dry season while others had these characteristics when produced in the wet months. Protein content generally decreased in wet-season-produced roots. However, a number of genotypes had comparable root quality and shelf-life regardless of planting season.     

冷藏三文鱼片微生物生长动力学模型适用性分析及货架期模型的建立

为研究不同冷藏温度(0,4,10℃)下三文鱼片中菌落总数、明亮发光杆菌、乳酸菌、假单胞菌以及产H2S细菌的生长情况,用不同的微生物生长动力学模型对其微生物生长动态进行非线性拟合,探究动力学模型对冷藏三文鱼片微生物生长的适用性,建立其剩余货架期模型。分别以一级化学反应动力学模型、修正的Gompetz模型、Baranyi and Roberts模型作为一级微生物生长动力学模型,描述微生物在恒定温度下随时间的生长规律;分别以Arrhenius方程和Belehradek方程(平方根模型)为二级模型,描述贮藏温度对微生物生长曲线的最大比生长速率(μmax)及延滞时间(λ)的影响。结果显示:Baranyi and Roberts模型方程能更好地描述冷藏三文鱼片中微生物的生长动态,拟合效果优于一级化学反应动力学模型和修正的Gompertz模型。Baranyi and Roberts模型方程所得参数用Belehradek方程拟合,结果发现冷藏三文鱼片微生物生长的最大比生长速率和延滞时间与贮藏温度呈良好的线性关系。由Belehradek方程建立的冷藏三文鱼片剩余货架期模型相对误差在(±18.90%)内,比Arrhenius方程建立的货架期预测模型预测更准确,可很好地描述菌落总数、假单胞菌、产H2S细菌及明亮发光杆菌随贮藏时间和温度的变化规律,预测冷藏三文鱼片的货架期。