Influence of the stage of ripeness on phenolic metabolism and antioxidant activity in table grapes exposed to different CO2 treatments

We have analyzed the influence of the stage of ripeness on L-phenylalanine ammonia-lyase (PAL) gene expression, accumulation of anthocyanins and total phenolics, and on antioxidant activity in the skin of table grapes treated with 20% CO₂ + 20% O₂ + 60 % N₂ for 3 or 6 d at low temperature (0 °C). The residual effect of high CO₂ treatment after transfer to air was also studied. In early harvested grapes, neither the anthocyanin content nor the accumulation of VcPAL mRNA was affected by any of the CO₂ treatments applied. However, in late harvested grapes, the duration of high CO₂ treatment determined its effect and a 6 d treatment with CO₂ sustained higher levels of total phenolics and anthocyanin accumulation, and VcPAL expression than observed in untreated late harvested grapes. The increased antioxidant capacity was correlated with the total amount of phenolics and anthocyanins. Conversely, in grapes treated for 3 d with CO₂ the phenylpropanoid pathway did not appear to be induced and a relationship between antioxidant activity and anthocyanins was not observed. Thus, further studies are needed to identify the most important antioxidants in these treated fruit.     

不同成熟期番茄热导率的测定

 采用微热探针法测定了同一品种不同成熟期番茄的热导率变化, 结果表明: 同一品种番茄热导率与其可溶性固形物含量存在着显著线性相关, 而与含水率和密度的相关性不显著。从这一结果可为番茄冷藏保鲜及制冷工业的定量研究参考。     

转基因番茄果实成熟与乙烯含量的关系

为探索番茄果实成熟与乙烯的关系,测定了转反义NR和ACC基因突变体番茄果实不同发育期乙烯释放量的变化,结果显示:(1)NR2、NR17和NR18号转反义NR基因果实各期的乙烯含量变化规律与普通果实相同。(2)转反义 NR基因番茄果实与转反义ACC基因番茄果实不同,前者果实能正常成熟、但成熟延迟,后者不能正常成熟。(3)在转反义NR基因果实发育各期中,粉红期乙烯释放量最高。(4)转反义NR基因果实成熟各期乙烯的释放量均明显低于普通果实。说明乙烯受体蛋白基因——NR基因的表达在被抑制后,也反过来抑制了番茄果实乙烯的释放。(5)转反义NR基因果实在常温下贮藏,贮藏期延长了43d。     

Metabolite accumulation in strawberry (Fragaria × ananassa Duch.) fruits and runners in response to Colletotrichum nymphaeae infection

The composition of non-infected and Colletotrichum nymphaeae infected strawberry fruits (cultivar ‘Asia') in three different stages of ripeness were evaluated. Additionally, the effect of infection on strawberry runners was monitored. C. nymphaeae infection caused a significant increase in total sugar content in mature fruits (1.1 fold) and a decrease in total sugar content in semi-mature fruits (1.4 fold) and organic acid content in all stages of ripeness (1.7 fold). Ellagic acid derivatives (1.9 fold), flavanols (1.5 fold) and flavonols (5.1 fold) significantly increased during all stages of ripeness after infection. The pattern of phenolic accumulation in strawberry runners was altered by C. nymphaeae infection in contrast to strawberry fruits as most of identified phenols decreased as a response to the infection.     

酿酒葡萄单品种酿造特性研究

分别对２１个世界优良酿酒葡萄品种的成熟及单品种酿造特性进行了研究，初步筛选出了适宜泰岭山区生态条件的品种：霞多丽，雷司令，黑彼诺，赤霞珠，歌海娜和适宜关中地区生态条件的品种，巴库斯。雷司令，白羽，法国寺，五月紫，品丽珠。     

沙城产区主栽酿酒葡萄品质的研究

研究沙城产区主栽酿酒葡萄品种赤霞珠(Cabernet Sauvignion)、梅鹿辄(Merlot)、马瑟兰(Marselan)、西拉(Syrah)和霞多丽(Chardonnay)的果实成熟度、采收日期和品质等。结果表明,不同品种的成熟特性存在差异,主要表现在果实含糖量上升与含酸量下降的速率不同,降雨量对果实含糖量和含酸量的影响较大,不仅推迟成熟期,而且影响成熟度。供试品种果实含糖量一般为210~240 g/L,果实含酸量一般为6~10 g/L,糖酸比(M值)25。供试红色品种果实丹宁含量为2.31~3.72 mg/g,总酚含量为2.06~3.35 mg/g,总花色素含量为0.96~2.36 mg/g,不同栽植区域存在差异。白色品种霞多丽果实丹宁、总酚的含量,东花园镇极显著地高于小南辛堡镇。除梅鹿辄和霞多丽外,供试其他品种在东花园镇的采收期较小南辛堡镇的采收期晚半个月左右。     

不同成熟度大团蜜露水蜜桃货架期间品质与代谢差异性研究

以大团蜜露水蜜桃为试材,测定了果实采后货架期间的呼吸速率、果实硬度、可溶性固形物含量、维生素C含量、果肉色差L*值、丙二醛含量,以及果实内SOD、POD、CAT、PG、CX等相关酶的变化,结果表明,货架期间,九成熟果实呼吸强度高,果实内含物质消耗的多,货架品质差;七成熟果实能保持较高的硬度,但呼吸速率较八成熟果实高,可溶性固形物、维生素C含量低,风味不足;八成熟果实采收后可以推迟果实呼吸高峰的出现和降低呼吸高峰值,能保持较高的可溶性固形物含量、维生素C含量,维持较高的SOD、POD、CAT等保护酶活性,丙二醛含量较低,生理活性强,有较长的果实货架生理周期,因此,八成熟可作为大团蜜露水蜜桃的货架、保鲜的适宜采收期。     

家蚕蛾的成熟度及交配时间对产卵的影响

通过试验调查表明,家蚕蛾的成熟度及交配时间长短,对蚕蛾的产卵量、产卵速度和卵质均有不同程度的影响.并提出蚕蛾最适成熟时间和交配时间.     

影响冰淇淋融化特性的因素研究

冰淇淋的抗融化性能是冰淇淋生产中非常重要的一项指标。主要从新型复合乳化稳定剂和配方中的营养素及加工条件等方面对冰淇淋融化特性的影响进行研究,试验采用对比试验设计。结果表明:新型复合乳化稳定剂的比例在0 4%为最佳配比;冰淇淋的抗融化性能随脂肪含量(6%～14%)和非脂乳固体含量(6 5%～14%)的增加而提高;而冰淇淋的抗融化性能随糖的含量(8%～20%)的增加而降低;冰淇淋的膨化率在80%～100%范围内、均质条件为60～70℃、15～20Mpa、4℃温度下老化4h等工艺条件可明显增加其抗融性。