高压对从桃渣中提取酚类物质影响的研究

考察高压对乙醇溶液提取桃渣中酚类物质的影响。结果表明,乙醇体积浓度70％比较适宜。随着处理压力的增大,酚类物质的得率逐渐升高（400MPa除外）,且在500MPa以前得率提高的幅度较大,压力到达600MPa以上后得率增幅不大。随着提取时间的延长,酚类得率先升后降,提取时间以10min为宜。酚类物质的得率先随温度升高而增大,到50℃达到最高,随后又下降。高压对乙醇溶液提取桃渣中酚类物质有显著的促进作用。     

高压对从梨渣中提取酚类物质影响的研究

考察高压对乙醇溶液提取梨渣中酚类物质的影响。结果表明,乙醇浓度70%(V/V)比较适宜。随着处理压力的增大,酚类物质的得率逐渐升高(400MPa除外),且在500MPa以前得率提高的幅度较大,压力到达600MPa以上后得率增幅不大。随着提取时间的延长,酚类得率先升后降,提取时间以10min为宜。酚类物质的得率先随温度升高而增大,到50℃达到最高,随后又下降。高压对乙醇溶液提取梨渣中酚类物质有显著的促进作用。     

不同澄清方式对苹果浓缩汁中酚类物质的影响

苹果浓缩汁中多酚类物主要有绿原酸、儿茶酚、儿茶酚等八种,其中以绿原酸含量最多,占总酚含量的大部分。不同的澄清方式都会使上述八种多酚类特质减少,但减少程度差异较大,超滤清法所得的苹果浓缩汁中的多酚物质大约只相当于硅藻土澄清法和明胶一酶一硅溶液澄清法制得的浓缩汁中的多酚物质的一半左右。     

从苹果渣中提取果胶的工艺研究

探讨了以苹果渣为原料提取果胶的最佳工艺条件,实验结果表明萃取液的pH值为2.0、料液比为1∶13、温度为85℃、水解时间为1.5h为提取果胶的最佳工艺条件,产率达14.04%。     

压榨对酿酒葡萄皮渣酚类物质提取及抗氧化活性的影响

酿酒葡萄皮渣（皮和籽）生物活性物质含量丰富,具有很高的再加工利用价值。对鲜葡萄皮渣进行压榨处理后再干燥,研究压榨对皮渣的酚类物质提取及抗氧化活性的影响。结果表明：压榨处理可以快速降低葡萄皮渣水分含量,缩短干燥时间、提高可溶性膳食纤维提取率。压榨葡萄皮总酚、原花青素的提取量均有所增加,其含量分别为19.56 mg/g和22.64 mg/g。压榨葡萄皮的抗氧化能力高于未压榨葡萄皮,其DPPH、ABTS及羟自由基清除率分别为62.90%、70.18%和41.09%,铁氰化钾还原能力及金属离子螯合能力分别为0.23%和21.33%。压榨籽和皮籽混合物的酚类物质和抗氧化活性则明显降低。抗氧化活性与总酚、原花青素存在显著的相关关系（P＜0.01）。     

苹果渣中多酚类物质的提取和应用研究进展

苹果多酚是苹果中多元酚类物质的总称,具有良好的保健和药理功能。本文主要论述了苹果渣中多酚类物质的组分、性质、生物活性以及干苹果渣中提取、纯化多酚类物质的研究及应用现状。      

苹果渣中多酚类物质的提取和应用研究进展

苹果多酚是苹果中多元酚类物质的总称,具有良好的保健和药理功能。本文主要论述了苹果渣中多酚类物质的组分、性质、生物活性以及干苹果渣中提取、纯化多酚类物质的研究及应用现状。     

从苹果渣中提取果胶工艺条件的研究

以苹果渣为原料,采用酸液提取、95%乙醇沉析的方法制取果胶,考察了酸液浓度、时间、料液比、温度等因素对果胶产量的影响,通过正交试验优化的提取工艺为：料液比1∶15（g/mL）,提取温度75℃,提取时间2.0h,酸液浓度0.3%,此条件下10g干苹果渣可提取果胶为1.37g。     

苹果渣中提取果胶工艺研究

以苹果渣为原料 ,采取酸液提取、酒精沉析的方法制取高甲氧基果胶。探讨了酸的种类对产品得率的影响 ,并以盐酸为代表研究了酸液浓度、料液比、加热温度和时间对产品得率的影响 ,确定了苹果渣中果胶的最佳提取条件。产品经有关部门检测 ,符合果胶质量标准 ,对生产成本也进行了估算。     

热协同高压处理对鲜榨苹果汁中酚类和VC的影响

探讨热协同高压对鲜榨苹果汁酚类和Vc的影响。结果表明：400MPa时，处理后酚类物质相比处理前的有所减少，差异显著（P〈0．05）。600MPa处理后各种酚类略有减少，但没有显著差异。压力为800MPa时，各种酚类物质的含量增加。40℃协同500MPa的处理后，果汁中酚类物质的含量与处理前相比没有显著差异（P〉0．05），50℃和60℃协同500MPa处理后，除了聚原花色素外、其他酚类比处理前显著增高外，果汁的L值显著升高，果汁色泽改善，但还原型Vc的损失明显大于单独压力处理的。     

毛诃子中总多酚的提取工艺研究

目的 比较不同提取条件对毛诃子提取物多酚含量的影响。方法 采用超声辅助溶剂萃取法, 利用响应曲面实验和正交实验单因素考察乙醇浓度, 料液比、提取时间和提取功率对提取物中多酚含量影响, 探索最佳提取工艺。结果 乙醇浓度为主要因素, 其次是提取时间, 再次是料液比, 而提取功率影响最小。乙醇55%、料液比1:38 g/mL、提取时间为12 min、提取功率为300 W时提取物中多酚含量达最高。结论 本研究确定了毛诃子中多酚的提取工艺; 响应曲面试验与正交试验相比更安全、可靠、精确。     

豆粕中大豆异黄酮提取工艺的优化

采用乙醇回流浸提和HCl水解两步法，从大豆豆粕中提取大豆异黄酮类化合物，以染料木素为标准物，在紫外区对异黄酮含量进行测定。通过正交试验确定最佳提取工艺。本实验平均回收率为95．7％。     

Influence of ultra-high pressure homogenisation on antioxidant capacity,polyphenol and vitamin content of clear apple juice

Ultra-high pressure homogenisation (UHPH) is a recently developed technology and is still under study to evaluate its effect on different aspects of its application to food products. The aim of this research work was to evaluate the effect of UHPH treatments on quality characteristics of apple juice such as antioxidant capacity, polyphenol composition, vitamin C and provitamin A contents, in comparison with raw (R) and pasteurised (PA) apple juice. Several UHPH treatments that include combinations of pressure (100, 200 and 300 MPa) and inlet temperatures (4 and 20 °C) were assayed. Apple juice was pasteurised at 90 °C for 4 min. Antioxidant capacity was analysed using the oxygen radical antioxidant capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) assay while total phenolic content was determined by the Folin–Ciocalteau assay. According to the FRAP and DPPH assays, UHPH processing did not change apple juice antioxidant capacity. However, significant differences were detected between samples analysed by TEAC and ORAC assays. In spite of these differences, high correlation values were found between the four antioxidant capacity assays, and also with total polyphenol content. The analysis and quantification of individual phenols by HPLC/DAD analytical technique reflects that UHPH-treatment prevented degradation of these compounds. Vitamin C concentrations did not change in UHPH treated samples, retaining the same value as in raw juice. However, significant losses were observed for provitamin A content, but lower than in PA samples.     

Synergistic impact of sonication and high hydrostatic pressure on microbial and enzymatic inactivation of apple juice

The combination of innovative, non-thermal technologies for the production of safe and quality fruit juices is a recent trend in food processing. The purpose of this study was to evaluate the effects of combined treatment of ultrasound (US) and high hydrostatic pressure (HHP) on enzymes (polyphenolase, peroxidase and pectinmethylesterase), microorganisms (total plate counts, yeasts and molds) and phenolic compounds (total phenols, flavonoids and flavonols) of apple juice. Moreover, its effects on ascorbic acid, antioxidant capacity and DPPH free radical scavenging activity, color values, pH, soluble solids and titratable acidity were investigated. Fresh apple juice was treated with US (25 kHz and 70% amplitude) at 20 °C for 60 min with subsequent HHP treatment at 250, 350 and 450 MPa for 10 min at room temperature. The results revealed that the combined US-HHP450 treatment caused highest inactivation of enzymes with complete inactivation of total plate counts, yeasts and molds. It also significantly improved the phenolic compounds, ascorbic acid, antioxidant capacity, DPPH free radical scavenging activity and color values. The present results suggest that the combination of US and HHP can act as a potential hurdle to produce safe and high quality apple juice with reduced enzymes and microbial activity and improved nutrition.     

A comparative study of changes in the microbiota of apple juice treated by high hydrostatic pressure (HHP) or high pressure homogenisation (HPH)

The objective of this study was to assess the effect of High Pressure Homogenisation (HPH) compared with High Hydrostatic Pressure (HHP) on the microbiological quality of raw apple juice during storage at ideal (4 °C) and abuse (12 °C) temperatures. In the case of HPH, only low numbers of micro-organisms were detected after treatment at 300 MPa (typically between 2 and 3 log.ml⁻¹). These were identified as Streptomyces spp., and numbers did not increase during storage of the juice for 35 days, irrespective of storage temperature. In the case of HHP, the total aerobic counts were also reduced significantly (p < 0.05) after treatment for 1 min at 500 and 600 MPa and the numbers did not increase significantly during storage at 4 °C. However, during storage at 12 °C the counts did increase significantly (p < 0.05) and by day 14 counts at 500 MPa were not significantly different from the control juice. This confirms that good temperature control is important if the full benefits of HHP treatment are to be realised.Frateuria aurantia dominated the microbiota of the HHP apple juice stored at 12 °C along with low levels of Bacillus and Streptomyces spp.The HPH and HHP juices both turned brown during storage indicating that neither treatment was sufficient to inactivate polyphenol oxidase. The enzyme is known to be pressure resistant and this discolouration was controlled by a heat treatment (70 °C for 1 min) used in commercial practice and given prior to HP treatment.     

Evaluation of high pressure pretreatment for enhancing the drying rates of carrot,apple, and green bean

Preservation of fresh produce by drying dates back to ancient times and is still an indispensible technique. Conventional drying of fruits and vegetables is often accompanied by changes in color, texture, and taste. Suitable pretreatments can improve the drying process by reducing the drying time, yielding higher-quality products, and energy savings. In this study, two varieties of apples, Amasya and red delicious, green beans and carrots were pretreated with high hydrostatic pressure (HHP) at different pressure–time–temperature combinations (100–300 MPa for 5–45 min at 20 and 35 °C) prior to drying. The drying experiments were carried out by using a hot-air tunnel dryer at different temperatures (27–85 °C) and air velocities of 0.4 and 0.8 m/s with constant external conditions. Improving the drying conditions by increasing the drying temperature generally masked the effect of HHP pretreatment on drying rate. Generally, pressures of more than 100 MPa caused cell permeabilization resulting in higher drying rates. Among 14 models, the modified Page model was found to best explain the drying behaviors and model constants were evaluated accordingly. The Tukey multiple comparison test was applied on characteristic drying times to evaluate the relative effects of different pretreatments and drying conditions.     

Evaluation of thermal and high hydrostatic pressure processed apple purees enriched with prebiotic inclusions

The effects of high hydrostatic pressure (500 MPa/1.5 min/20 °C) and mild conventional pasteurization (P₉₀ > 10 min) processing on the fructan content, polyphenolic stability and physico-chemical characteristics of apple purees enriched with two commercial prebiotics [Beneo GR® (inulin) and HSI® (fructooligosaccharides—FOS)] over 30 days at 4 °C were evaluated. Fructan analysis showed that the prebiotics were stable throughout 30 days and were present in sufficient quantities to deliver a prebiotic effect. Fluctuations in physico-chemical characteristics were more evident in purees containing inulin than FOS. Sensory acceptability of purees was deemed acceptable (> 3) by panellists and showed no preference for either processing type. Minor deterioration in acceptability was observed in thermal processed samples containing inulin inclusions during storage (p < 0.05). Processing reduced (p < 0.05) the levels of some polyphenolic compounds in all samples compared to unprocessed controls, in particular chlorogenic acid and phloridzin, which were largely responsible for overall decreases in total phenolic index (TPI).

Industrial relevance

Studies have shown that high hydrostatic pressure processing (HHP) can better retain inherent functional components i.e. antioxidant compounds, compared to mild pasteurization. However, processors need to be assured that further additions of functionally beneficial components, such as prebiotics, are similarly protected. This study focussed primarily on assessing the effect of thermal and HHP on the stability of two prebiotics over storage (30 days at 4 °C). Results indicate that both prebiotics were stable and present in sufficient quantities to deliver a prebiotic effect for both processing types after storage. In some cases, less hydrolysis of the prebiotic occurred in HHP purees. These outcomes could help the food industry identify the optimal processing type to maximise retention of added and inherent functional properties.