Polyphenol content and antioxidative activity in apple purées with rhubarb juice supplement

The purpose of the present study was to evaluate the effect of rhubarb juice addition and peeling in apple purée production and storage on its phenolic composition, antioxidant activity and colour. The apple material used in this study was of two varieties: Sampion and Idared. The apple purées prepared in three variants (control purées, peeling purées and purées with 5% of rhubarb juice) were stored for 3 and 6 months at 30 °C. Apple purées were investigated for their antioxidant activity, change of colour and contents of phenolic compounds plus the polymer procyanidins and degree of polymerization (DP). The preparation of purées from apples without peeling and the addition of rhubarb juice during purée preparation had significant influence on polyphenol content. The purée prepared from peeled apples of Idared variety had phenolic content 2.2 times lower than the control sample (non‐peeled apples). The highest level of total polyphenols was found in Idared + rhubarb sample (129.82 mg 100 g^?1 purée). The content of this compound in Idared control sample was more than 2.8 times lower than in Idared purées with rhubarb. The use of non‐peeled Idared apples and 5% of rhubarb juice in purée preparation significantly increased polymeric procyanidins from 11.68 to 75.20 mg 100 g^?1 and other phenolics from 9.23 to 54.62 mg/100 g. This effect for Sampion apples was smaller. The procyanidins during purées storage were more stable in samples with rhubarb juice addition. The purée samples with the addition of rhubarb juice had higher antioxidant activity measured using ABTS (2,2′azinobis‐(3‐ethylbenzthiazoline‐6‐sulphonic acid)) than purée samples without the addition (two times higher for Idared variety) of rhubarb juice. After 3 and 6 months of storage at temperature 30 °C, the antioxidant capacity decreased in all purées. Rhubarb juice had only high and positive effect on L* value in the case of Idared variety. The results showed that all Sampion apple purées had higher L* values than Idared.     

Fruit‐based functional foods I: production of food‐grade apple fibre ingredients

With the increased consumer interest in fibre‐enriched functional foods, industrial‐scale methods for functional fibre production are demanded. The development of a food‐grade fibre preparation method at lab scale that is feasible for industrial scale‐up is a pre‐requisite. This paper describes two lab‐scale fibre preparation methods that have potential to be scaled up to industrial setting for the production of fruit fibres containing desired bioactives and functionality. The two methods, one aqueous and the other ethanolic, were used to isolate fibres from Granny Smith apples (Malus domestica Borkh cv. ‘Granny Smith’). In the aqueous method, ground apple tissues were suspended in HEPES buffer (20 mM, pH 6.5), and then mechanically ruptured using an Ultra‐Turrax and ring grinder. Between steps, the cell‐wall materials were washed with the HEPES buffer. In the ethanolic method, ground apple tissues were stirred in 72% ethanol at 4 °C, filtered, re‐suspended in 72% ethanol and then washed. Microscopic examination and chemical analysis were performed on the resultant fibres. The aqueous method produced natural and uniform dietary fibres in the form of plant cell walls containing 0.282 g uronic acid per g dried fibre. By comparisons, the ethanolic method produced crude fibres containing only 0.182 g uronic acid per g dried fibre, the lower uronic acid content indicating the presence of impurities. Thus, the aqueous method appeared to be advantageous in terms of the retained pectic polysaccharide content and cost‐effectness for industrial scale‐up. Further characterisation using Folin‐Ciocalteu assay and high performance liquid chromatography indicates that the fibres obtained by the aqueous method contained significant amounts of phenolic compounds (2.6 mg catechin equivalent per g dried fibre). These results suggest that fibres obtained by the aqueous method may be more suitable for functional food applications where fibres with high pectic polysaccharide and beneficial phenolic antioxidants are preferred.     

Suppression of postharvest blue mould of apple fruit by Cryptococcus laurentii and N6‐benzyladenine

BACKGROUND: Cryptococcus laurentii is a well‐known postharvest yeast antagonist. N⁶‐benzyladenine (6‐BA), a cytokinin plant hormone, has a role in retarding ripening and senescence of harvested produce. This study was conducted to evaluate the efficacy of C. laurentii and 6‐BA in reducing the blue mould disease of apple fruit. RESULTS: The combination of C. laurentii with 6‐BA (20 µg mL^?1) was more effective in suppressing the Penicillium expansum infection in apple fruit wounds than C. laurentii alone, although 6‐BA (20 µg mL^?1) alone neither affected the growth of C. laurentii nor reduced the incidence of the blue mould disease in vivo. Moreover, treatment of apple fruit with C. laurentii and 6‐BA (20 µg mL^?1) resulted in stimulation of superoxide dismutase activity but in inhibition of the increase in peroxidase activity. CONCLUSION: 6‐BA (20 µg mL^?1) could enhance the efficacy of C. laurentii in reducing the postharvest blue mould disease of apple fruit, which offered great potential in minimizing the postharvest decay of apple fruit in an integrated pest management strategy. Copyright © 2008 Society of Chemical Industry     

果蔬土壤中重金属元素Zn,Hg,Cu含量的测定

以甘肃省天水市麦积区花牛镇花牛村苹果种植地区土壤为研究对象采用火焰原子吸收光谱仪对土壤中的重金属元素Zn,Hg,Cu的含量进行了测定,各重金属元素的平均含量分别为:Zn的平均含量为26.27 mg/kg、Hg的平均含量为0.617 mg/kg、Cu的平均含量为11.67 mg/kg。结果表明,该地区的土壤可以安全的进行农业生产,土壤中的重金属不会通过食物链的作用对人类健康形成威胁和危害。     

富士苹果果皮中花青素含量测定

苹果中花青素的主要成分为矢车菊素-3-半乳糖苷。文章研究了苹果中矢车菊素-3-半乳糖苷提取的条件与测定方法。提取条件为:以1.00%盐酸甲醇溶液为提取溶液,在温度40℃下超声提取60min。在优化的条件下,首次对北京昌平、陕西白水、山东烟台等3个不同地区长富2号苹果果皮的矢车菊素-3-半乳糖苷含量进行测定。在3个地区的9个果园的样品矢车菊素-3-半乳糖含量在4.51～14.7μg/cm2之间,其中陕西白水苹果含量最高,平均含量达14.0μg/cm2。     

木瓜复合果醋的酿制

以湖北长阳县的木瓜为基料，配以含糖量较高的苹果汁，制备营养丰富的复合木瓜果醋。结果表明，木瓜汁与苹果汁制成的复合果醋，色泽清亮自然，具有两种果汁的复合香味，口感和香味都优于纯木瓜醋和木瓜菠萝复合果醋。     

1-MCP处理对"美国8号"苹果采后生理的影响

以“美国8号”苹果为试材，研究了0℃贮藏条件下1-MCP（1-甲基环丙烯）处理对果实采后生理的影响。结果表明：1μL/L1-MCP处理可显著抑制贮藏期间果实乙烯释放量，延缓其跃变高峰的出现，推迟ACO（ACC氧化酶）活性高峰及呼吸跃变峰的出现，抑制采后初期ACO活性及呼吸速率的上升；减缓果肉硬度下降；同时降低脂氧合酶（LOX）活性，并延迟其峰值的出现，延缓了丙二醛（MDA）含量和相对膜透性的升高，从而降低膜脂过氧化程度。结果表明：1-MCP可显著改善其贮藏品质。     

利用苹果渣制备膳食纤维的工艺研究

以苹果渣为原料，利用单因素实验和正交实验研究了可溶性膳食纤维和不溶性膳食纤维的提取工艺。本文是前一部分制备可溶性膳食纤维的实验。结果表明：提取可溶性膳食纤维A的最佳工艺条件是粒度40目，0．3％盐酸溶液，液料比15：1（ml/g) ,温度80℃时，反应2.0h；可溶性膳食纤维B的最佳工艺条件是8％NaOH溶液，液料比8：1（ml/g)，温度90℃时，反应3.0h。     

Occurrence of patulin and 5-hydroxymethylfurfural in apple sour,which is a traditional product of Kastamonu,Turkey

Apple sour is a traditional product of Kastamonu, Turkey. It is consumed by spreading on bread or drinking after diluting with water. The aim of this study was to determine patulin (PAT) and 5-hydroxymethylfurfural (HMF) in apple sour. This study is the first to evaluate the occurrence of PAT and HMF in apple sour. The samples were extracted with ethyl acetate using liquid-liquid extraction technique. PAT and HMF were determined by HPLC with UV detection. PAT was detected in all samples, and the PAT level in 94.9% of samples was found to be equal or greater than the legal limit for juice concentrates. The mean value for PAT was found to be 284 ± 307 μg kg^?1. PAT levels in 13 of 39 samples were in the range of 100 ≤ x < 200 μg kg^?1, two samples were in the range of 0 ≤ x < 50 μg kg ?1 and two samples were in the range of 1000 ≤ x < 1500 μg kg¹. HMF levels of all samples were above the legal limit for solid molasses. The mean value for HMF was found to be 16215 ± 13317 mg kg^?1. HMF levels of 10 of 39 samples were determined to be in the range of 10000 ≤ x < 20000 mg kg^?1, eight samples were in the range of 20000 ≤ x < 30000 mg kg^?1 and only three samples were in the range of 100 ≤ x < 1000 mg kg^?1. There was a significant and inverse relationship between HMF and pH of the samples. These results indicate that consumption of apple sour is a considerable risk in terms of HMF and PAT toxicity.     

苹果多酚的促排铅功效研究

采用小鼠腹腔注射乙酸铅溶液10d,建立染铅小鼠模型,连续15d灌胃给予苹果多酚,研究苹果多酚的促排铅作用。石墨炉原子吸收法测试血铅、尿铅、粪铅和股骨、肝脏中铅含量。结果表明:染毒小鼠给予苹果多酚后,血铅和股骨、肝脏中铅含量明显低于阳性对照组,而尿铅明显高于阳性对照组。苹果多酚具有明显的促排铅效果。