肉桂油及其β-环糊精包合物对鲜切西瓜的保鲜效果

以鲜切西瓜为试材,设置肉桂油(cinnamon oil,CO)、CO-β-环糊精(β-cyclodextrin,β-CD)包合物和空白对照3个处理组,通过测定微生物和品质指标变化,研究CO及其β-CD包合物对鲜切西瓜的保鲜效果。结果表明:贮藏期间,鲜切西瓜质量损失率、菌落总数和可滴定酸质量分数呈现增加趋势,L~*值和a~*值呈现下降趋势,可溶性固形物含量先增加后下降,上述指标冷藏比常温贮藏变化缓慢;其中CO-β-CD包合物(含CO 0.040 8 g/100 g西瓜)结合4℃冷藏处理对鲜切西瓜保鲜效果最好,可以有效抑制西瓜质量损失率和可滴定酸质量分数的增加,降低西瓜褐变程度,保持西瓜较高可溶性固形物含量;冷藏4 d,该处理条件下西瓜菌落总数显著低于对照和其他处理组(P0.05),感官分数显著高于对照和CO处理组(P0.05),仍然具有商品价值。CO被β-CD包埋后稳定性提高并可以掩盖肉桂醛气味,有效维持西瓜品质,延长保质期,在鲜切西瓜保鲜上具有较好的应用前景。     

70%噻虫嗪WS处理打瓜种子防治地下害虫的药效试验

为验证70%噻虫嗪种子处理可分散粉剂(WS)对打瓜地下害虫的防治效果,采用拌种法,分别用种子量0.1%、0.2%和0.4%的剂量处理打瓜种子进行防治地下害虫的药效试验。结果表明:不同剂量药剂处理出苗率均在85%以上;对苗期地下害虫的平均防效分别为77.55%、83.67%、87.75%,且对打瓜生长无不良影响。     

西瓜籽油辅助降血脂功能研究

以高脂血症大鼠为试验动物,研究西瓜籽油的辅助降血脂作用。将48只雄性Wistar大鼠分成6组,其中阴性对照组和高脂对照组给予蒸馏水,阳性对照组每日灌胃0.06 g/kg血脂康,3个试验组每日分别灌胃2.6、7.7、13.0 g/kg西瓜籽油。阴性对照组给予基础饲料,其余各组给予高脂饲料喂养。灌胃30 d后检测大鼠血脂水平,并将肝脏进行病理切片,比较各组大鼠的血脂差异。结果表明:各剂量组大鼠血清总胆固醇、甘油三酯、低密度脂蛋白胆固醇含量不同程度低于高脂对照组,高密度脂蛋白胆固醇含量显著高于高脂对照组;各剂量组大鼠血清和肝脏超氧化物歧化酶、谷胱甘肽过氧化物酶含量显著高于高脂对照组,丙二醛含量低于高脂对照组;肝脏病理切片也显示各剂量组大鼠的脂肪变性得到不同程度改善。以上结果表明西瓜籽油能够降低高脂血症大鼠血脂水平,以2.6 g/kg剂量效果最佳。     

西瓜豆瓣酱研制及其亚硝酸盐含量研究

首先在传统西瓜豆瓣酱制作的工艺基础上,设定西瓜、花生油的添加量为150,10 g,通过将影响西瓜豆瓣酱风味的主要因素豆曲、盐、花椒、八角、小茴香、葱、姜、蒜的添加量进行单因素和正交试验,确定自制西瓜豆瓣酱的较优配方。试验结果表明,西瓜150 g、豆曲30 g、盐10 g、花椒1 g、八角2 g、小茴香1 g、葱8 g、姜12 g、蒜8 g为最佳配方。另外,研究了西瓜与豆曲的比例对亚硝酸盐的影响及西瓜豆瓣酱发酵成熟后随放置时间增加亚硝酸盐含量的变化。研究表明,在相同食盐添加量下,亚硝酸盐含量随着西瓜添加量的下降而降低,自制豆瓣酱亚硝酸盐含量随着放置时间的增加而降低并逐渐接近于平稳。根据GB 2762-2017《食品安全国家标准食品中污染物限量》对于蔬菜类食品规定亚硝酸盐含量不得超过20 mg/kg[1],食用不会对人体产生危害,为人们在加工西瓜豆瓣酱时提供了参考。     

不同产地西瓜农药残留分析与膳食风险评估

为明确不同产地西瓜农药残留状况,区分不同产区残留农药不同之处,本研究以新疆、山东、广西80个西瓜样品为研究对象,明确其60种农药残留水平的基础上,通过英国兽药委员会兽药残留风险排序方法对三产地西瓜残留农药进行排序、比较,并通过急性、慢性膳食摄入风险对其安全水平进行评估。结果显示:三产地共检出11种农药残留,新疆、山东、广西西瓜中残留农药种类分别为6、7、8种,且残留水平不同,检出农药风险得分也不同,其中广西检出的农药三唑磷、敌敌畏、咪鲜胺、苯醚甲环唑(24.60、24.60、18.30、18.15),山东检出的农药苯醚甲环唑、丙溴磷(18.50、18.10),新疆检出的农药农药苯醚甲环唑(18.20)风险得分相对较高。对检出农药进行急性、慢性膳食摄入风险结果显示西瓜中所有残留农药其%ADI、%ARf D值分别在0.01%～1.53%、0.03%～23.30%之间不等,其结果远小于100%。三地区样品中检出农药残留种类、残留水平、风险得分不同,需要根据产区重点关注相应农药,但残留农药水平属于安全限量内。     

Chemical,antioxidant and sensory properties of tomato‐watermelon‐pineapple blends,and changes in their total antioxidant capacity during storage

A conductometric analysis of the effect of condensate of peroxides generated during lipid oxidation in an accelerated stability test was adapted to test the hypothesis that total antioxidant capacity of tomato products would sometimes increase during processing and in storage. Tomato pulp blends made from a mixture of tomato (Lycopersicon esculentum var Roma VF), watermelon (Citrullus vulgaris var Babylack) and pineapple (Ananas comosus var Smooth cayennes) were analysed for basic quality profiles of dry matter, Brix, titratable acidity (TTA) and pH, total reducing sugars, Component antioxidants phytochemicals and total antioxidant capacity. The lowest sensory score (overall impression) of 4.80 ± 2.59 was recorded for tomato juice while, blend TWP 111p had highest score of 6.20 ± 1.99. There was significant difference (P < 0.05) in the basic quality profile of the pulp blends except for TTA values (0.37 ± 0.02 to 0.45 ± 0.05) and 2‐Furfurals (2.47 ± 0.03 to 2.71 ± 0.01). The fresh blend of 50% tomato, 25% watermelon and 25% pineapple had the highest total antioxidant capacity of 3.69 ± 0.52 mg 100 mL^?1 catechin equivalent. The total antioxidant capacity of the stored pulp increased from 2.95 ± 0.13 to 6.22 ± 0.32 mg 100 mL^?1 catechin equivalent in pasteurised TWP 211p blend by 60 days when stored at 40 °C. Total antioxidant status of tomato‐based fruit mix increased during the first 80 days.     

Effects of rind removal on physicochemical quality characteristics of fresh‐cut watermelon [Citrullus lanatus (Thunb) Matsum & Nakai] during cold storage

The impact of removing the rind from fresh‐cut watermelon slices was assessed on the quality of the product during storage at 4 °C for 9 days. Flesh lycopene declined from 55.4 to 47.9 mg kg^?1 f.w. and colour lightness (L*) increased from 43.2 to 45.8 after 2 days of storage. Initial heart and placental flesh firmness increased from 7.3 and 9.8 N, respectively, to 9.5 and 12.8 N after 9 days, but were unaffected by rind processing. Electrolyte leakage from placental tissue was unaffected by storage and rind. Rind presence limited juice run‐off by 47.2% and maintained mean total soluble sugar concentration in the slices at 86.0 mg mL^?1 as opposed to 76.8 mg mL^?1 in rind‐less slices. Change in the quality was most pronounced between 0 and 2 day of storage. Removing the rind accelerated senescence and off‐flavour production, while the presence of rind improved the overall storage stability of fresh‐cut watermelon slices.     

高压CO_2处理对西瓜汁的影响

以海南麒麟西瓜为原料,榨汁后进行HPCD(高压CO2)杀菌处理,处理温度为25℃,压力为20 MPa和30 MPa,处理时间分别为10、30和60 min,测定HPCD处理后西瓜汁的主要理化指标、细菌总数和PME酶(果胶甲基酯酶)活性变化。结果表明:HPCD处理后西瓜汁pH值降低0.3～0.7、可溶性固形物无明显变化、颜色更红、浊度增加,细菌总数降低可达到2个对数,果胶甲基酯酶活性可降低50%。     

西瓜藤中黄酮类化合物提取工艺的优化

采用乙醇溶液提取西瓜藤中总黄酮,通过单因素试验和正交试验研究了固液比、提取时间、提取温度和乙醇浓度对总黄酮提取率的影响。结果表明,最优提取条件为：固液比1∶20、提取时间4h,提取温度80℃、乙醇浓度60%。