The applied pretreatment (blanching,ascorbic acid) at the manufacture process affects the quality of nectarine purée processed by hydrostatic high pressure

A nectarine purée was manufactured with different pretreatments (thermal blanching or ascorbic acid – AA – addition), and then, the purée was processed by high‐pressure treatment to evaluate the effect of the initial manufacture conditions in the stability of the processed purées. A thermal treatment was also carried out to compare the effect with the high‐pressure processing (HPP). All applied processes were effective to ensure the microbiological safety of the purées. However, the pretreatment (thermal blanching or AA addition) applied during the manufacture affected the final quality of the processed purées. Initially, the AA addition had a protective effect on colour degradation during the manufacture of the purées; however, when these purées were treated by HPP showed less colour stability during storage, lower bioactive compounds content, and antioxidant activity. In contrast, purées with an initial thermal blanching maintained better the quality after HPP and during storage.     

不同浓度赤霉素处理对油桃保鲜效果的影响

以油桃为试材,用浓度为150mg／kg、200rag／kg、250mg／kg的赤霉素溶液涂膜处理30min,定期测定油桃果实的各项指标,研究赤霉素对油桃保鲜效果的影响。结果表明,经过赤霉素溶液涂膜处理,有效地减轻了油桃果实的失重现象、推迟了呼吸跃变出现时间、延缓了糖分和VC损失,有防止腐烂、保持硬度作用;对含酸量影响不大,其中浓度为200mg／kg的赤霉素溶液对油桃果实进行涂膜处理保鲜效果最好,能够较长时间的保持油桃果实的贮藏品质。     

油桃果皮红色素的微波提取工艺及特性研究

对油桃皮红色素的微波提取及理化特性进行了研究,结果表明,该色素为水溶性多酚类花色素,在不同的pH环境下显示不同的颜色;其耐热性、耐光性、耐酸、耐糖、耐还原性较好;但耐氧化性、耐碱性较差;Fe3 对色素有破坏性。研究还表明,该色素的提取宜在酸性介质中进行,酸性条件下其综合稳定性较优,有较高的利用价值。     

日光温室油桃滴灌灌溉制度试验研究

根据日光温室油桃不同物候期的需水特征,选择灌水量和灌水周期作为试验因素,设立不同灌水处理开展滴灌灌溉制度试验,为设施油桃的种植提供技术支持。结果显示:日光温室油桃年生长周期持续约365 d,适宜的灌水次数为22次,平均灌水周期为16 d,平均灌水定额为185 m3/hm2,年生长周期灌溉定额为4 080 m3/hm2,油桃产量可达3.0万kg/hm2以上。     

不同时期套袋对“瑞光19号”油桃果实挥发性成分及着色的影响

为探讨不同时期套袋对油桃果实风味品质的影响,对陕西关中主栽油桃品种"瑞光19号"进行了3个不同时期的桃专用果袋套袋实验。以不套袋果实为对照,利用固相微萃取-气相色谱-质谱联用技术测定果实的挥发性物质。结果表明:供试桃共检测到83种挥发性物质。其中特征香气物质的总含量从高到低的顺序为:对照盛花后40 d套袋(2014年5月14日)盛花后45 d套袋(2014年5月19日)盛花后50 d套袋(2014年5月24日)。与不套袋果实相比,不同时期套袋果实均提高了醇类物质的相对含量,但降低了醛类、酯类和酮类物质的相对含量;本实验共检测到3种内酯类和2种萜类特征香气物质,其中芳樟醇和γ-癸内酯存在显著相关性;此外,套袋主要影响了"瑞光19号"果实的香气成分和果面着色情况,果实套袋时间越早着色越好,其中盛花后40 d套袋后果实的着色好并且果香味浓,综合表现最佳。     

油桃采后结合态香气变化规律及其与可溶性糖的关联性

以‘瑞光1号’油桃为研究对象,研究其采后常温（20 ℃）和低温（1 ℃）贮藏下游离态和结合态香气物质变化规律。采用酶解法释放结合态香气物质,利用顶空固相微萃取法结合气相色谱-质谱联用对油桃游离态和结合态香气物质分别进行定性和定量分析,并研究结合态香气物质与可溶性糖之间的相关性。结果表明,油桃果实常温和低温贮藏条件下游离态和结合态香气物质种类存在很大差异。常温贮藏下检测到油桃中游离态香气物质37 种,结合态香气物质30 种,其中8 种物质以游离态和结合态2 种形式存在。游离态香气物质第4天下降至最低值后第6天有所上升,第8天含量有所下降,结合态香气物质第6天降至最低值后第8天有所上升。低温贮藏下检测到游离态香气物质21 种,结合态香气物质32 种,其中7 种物质以游离态和结合态2 种形式存在。随着低温贮藏时间延长,游离态香气物质含量下降,结合态香气物质呈现先上升后下降的趋势。相关性分析表明结合态香气物质含量与果实中可溶性糖含量之间显著相关,与蔗糖的相关系数最高。     

植物内生多粘类芽孢菌对油桃采后青霉病抑制效果的研究

本实验以植物内生多粘类芽孢杆菌作为生防菌种,研究该菌对油桃青霉病的抑制效果。研究了对油桃表面不同消毒方法(酒精消毒、紫外线消毒、无菌水消毒)的效果,以及生防液和其不同处理液(生防菌液、无菌液、热处理液、离心上清液)对油桃采后青霉病的抑制效果。实验表明:酒精对油桃表面的消毒效果最好,紫外线消毒次之,无菌水较差;生防菌液的抑制效果最好,无菌液和离心上清液次之,热处理液有很微弱的抑制效果。     

Identification of key odor volatile compounds in the essential oil of nine peach accessions

BACKGROUND: Volatile compounds, together with sugars and acids, are the main chemical species determining the characteristic aroma and flavor of food. In peach, more than 100 volatiles have been identified. RESULTS: The essential oil of six peach and three nectarine accessions used in Italian breeding programs was obtained by steam distillation, and the volatiles were investigated. A total of 47 known volatiles, two unidentified compounds and nine hydrocarbons were identified, including 12 aldehydes, six alcohols, three acids, three esters, six terpenes, two phenylalanine derivates, two C₁₃ norisoprenoids, one ketone (C₉) and 10 lactones. A wide variation in the number of volatiles and in their concentration was observed among the nine accessions. Twenty‐one compounds presented odor activity values (OAVs) higher than 1 in at least one of the accessions and were therefore putatively considered as key odorants in the peach volatile composition. CONCLUSION: This study reports the identification, quantification and potency, based on the OAVs, of the most important volatile compounds, along with fruit quality characteristics, of nine different peach/nectarine accessions and will help future peach volatile breeding programs for the selection of odor‐rich accessions to be used in the development of new improved cultivars. Copyright © 2010 Society of Chemical Industry     

不同保鲜袋包装对采后油桃果实贮藏品质的影响

目的研究常温环境下不同保鲜袋包装处理对油桃果实贮藏品质的影响。方法以黄心油桃为实验材料,比较相同厚度的聚丙烯(PP)、双向拉伸聚丙烯(BOPP)和聚乙烯(PE)薄膜包装袋对油桃果实贮藏品质的影响,筛选出合适的薄膜包装材料。结果采用3种保鲜袋包装对油桃果实的贮藏品质存在不同程度的影响,各处理组的油桃果实都发生了不同程度的腐烂褐变;未包装的油桃果实很快失去了食用价值,在贮藏12 d时褐变指数为4.5,腐烂率为65.33%;采用BOPP保鲜袋包装的油桃果实在贮藏12d时褐变指数仅为2.3,腐烂率仅为32.29%,果实出汁率保持在58%以上;BOPP保鲜袋包装处理的油桃果实在出汁率、TSS、TA、Vc、MDA等营养指标和衰老指标上均不同程度优于PP和PE保鲜袋包装的油桃果实。结论采用BOPP薄膜材料包装的油桃果实在常温贮藏下有较好的保鲜效果,有效地延长了油桃果实的货架期。