柿果脱涩机理及人工脱涩方法

<正>柿的涩味主要来自果肉中的单宁物质(C14H20O9),柿果是诸多果实中单宁含量最多的水果。日本学者梶浦(1946)根据果实脱涩与果肉褐斑形成和种子数目的关系,将柿分为完全甜柿、完全涩柿、不完全涩柿和不完全甜柿4个品种群。我国传统产区主要栽培完全涩柿,自‘罗田甜柿’被发现和确认为我国第1个原产完全甜柿种质以来,又相继报道了‘宝盖甜柿’和‘秋焰甜柿’(鄂柿1号)等,但迄今尚未发现我国原产的不完全涩柿和不完全甜柿品种。本文主要对完全甜柿和完全涩柿2个品种群柿果的脱涩机理及完全涩柿人工脱涩方法进行阐述,旨在为果树生产者提供参考。     

柿果脱涩

由于柿果单宁含量高，除甜柿以外，所有柿果采后均需经过脱涩处理方能食用。脱涩原理：一是用乙醇、乙醛、石灰水等直接与果实中的单宁作用，使可溶性单宁变为不溶性单宁，从而使柿果脱涩；二是将柿果置于无氧环境中，使其进行无氧呼吸，产生乙醇，乙醇经氧化变成乙醛，乙...     

甜柿的生物学特性及品种介绍

甜柿的生物学特性及品种介绍苏彩虹，郭创业，雷雪梅，王会金（山西省农科院棉花研究所运城０４４０００）柿子有两种，即涩柿和甜柿。涩柿果实中含有单宁细胞，当人们咬破果实时，可溶性单宁即溶于唾液中，使人感到强烈的涩味，所以涩柿在实用时需要脱涩或软化。甜柿成熟...     

太行山中部地区日本甜柿引种试验

柿子是深受消费者欢迎的水果,依果实能否在树上自然脱涩分为涩柿和甜柿两大类。甜柿能在树上自然脱涩,成熟果可溶性单宁为0.5%以下,食用方便,深受人们喜爱,称之“柿果珍品”。河北省太行山区是全国柿子主产区之一,由于当地品种大红袍柿、绵瓤柿等,果实中含单宁物质多,采后...     

柿果实脱涩技术研究进展

(Diospyros KaKi L.f.)属柿树科Ebenaceae柿 属，一般分为甜柿和涩柿两类，涩柿较甜柿含有更多的可溶性糖、有机酸，色泽也更鲜艳。我国种植的柿子大部分是涩柿,河北省是全国柿子生产大省，1997年柿子产量188173吨(《中国农业文摘》1998年)，居首位。柿果营养丰富，风味独特，深受人们喜爱，但涩柿未经脱涩难以入口，必需经过脱涩方可食用，提高其商品价值。 1.柿果实的脱涩原理 目前，人们普遍认为柿的涩味物质主要来自果肉中的单宁，它存在于单宁细胞的原生质中。单宁分为两类，一类是可溶性单宁(ST)，与蛋白质凝固产生收敛性物质而使…     

柿果脱涩技术

柿子果肉中含有大量的单宁,在果实成熟过程中逐渐由可溶性转化为不溶性.甜柿采收前在树上即可转化,失去涩味(因不溶性单宁不溶于唾液而使人感觉不到涩味),采下后便可食用.但涩柿硬熟期采后仍有相当多的可溶性单宁存在,涩味仍然严重,须经脱涩后方可食用.     

新鲜柿脱涩技术

1脱涩的原理柿果实内含有一种特殊的细胞,它的原生质里含有很多单宁物质,被称为单宁细胞。涩柿果实中的单宁,绝大多数以可溶性状态存在于单宁细胞内。当人们咬破果实后,部分单宁流出来,被唾液溶解,使人感到有强烈的涩味。甜柿果实中的单宁,绝大多数以不溶性状态存在,当人们咬破果实后,单宁不为唾液所溶解,所以不会感到有涩味。脱涩,就是将可溶性单宁变为不溶性单宁,并不是将单宁除去或减少,这种变化在单宁细胞内较容易进行。2脱涩的作用柿脱涩的作用大致分两种:直接作用和间接作用。2.1直接作用用酒精、石灰水、食盐等化学物质,渗入单宁细胞…     

完全雄性柿种质‘雄株8号’作为中国甜柿育种亲本的可能性研究

‘雄株8号’是中国中部大别山区分布的完全雄性柿种质,可能源自中国原产完全甜柿(中国甜柿)的杂交后代或是其自然变异,其作为完全甜柿专用授粉品种的可能性已有研究报道,但其作为完全甜柿育种亲本的应用潜力尚不明确。以‘华柿1号’(不完全涩柿)ב雄株8号’的杂交后代单株为试材,以常见中国甜柿、日本甜柿和非完全甜柿为对照,对其果实进行可溶性和不溶性单宁含量、单宁细胞大小等指标测定,确认杂交后代单株H8-2为具中国甜柿自然脱涩特点的完全甜柿类型。现有完全甜柿自然脱涩性状遗传特点的研究结果认为,只有日本甜柿相互杂交,或者是亲本之一为中国甜柿时,F_1才可能出现完全甜柿单株。该研究结果首次证明中国原产完全雄性柿种质‘雄株8号’带有控制自然脱涩性状的显性基因,因此其在完全甜柿遗传改良中具有作为育种亲本的应用潜力。     

‘南通小方柿’乙醇脱氢酶基因DkADH1的克隆及表达分析

以‘南通小方柿’果实为材料,采用同源克隆的方法,获得了柿乙醇脱氢酶基因DkADH1,其全长为1 377 bp,开放阅读框为1 137个核苷酸,编码379个氨基酸,具有ADH基因典型的结构域和功能域,与番茄、苹果等双子叶植物亲缘性较近。以‘南通小方柿’不同组织为材料,采用qRT-PCR方法对DkADH1及单宁生物合成途径中的相关基因的表达进行分析,同时测定了不同时期果实的单宁含量,结果表明在果实发育过程中,可溶性单宁含量逐渐降低,而不溶性单宁含量不断升高;DkADH1基因在茎、叶、花、果实等器官中均有表达,在果皮中表达量最高。随着果实的成熟,DkADH1表达量总体呈上升趋势。柿果实中单宁合成途径中的相关基因DkF3′5′H和DkMYB4随着乙醇处理果实时间的延长表达量呈下降趋势,推测‘南通小方柿’DkADH1能够抑制单宁合成相关基因的表达,从而降低果实可溶性单宁含量。     

磨盘柿温水脱涩过程中单宁含量及自由基清除能力的变化

 通过研究磨盘柿果实温水脱涩过程中单宁含量和ABTS［2,2–联氮–二（3–乙基–苯并噻唑–6–磺酸）］自由基清除能力的变化,进一步为涩柿果实利用及营养评价提供参考依据。采用40 ℃温水对磨盘柿进行脱涩处理,测定了脱涩过程中果实硬度、可溶性固形物、单宁含量、总酚含量及ABTS自由基清除能力的变化。经24 ~ 27 h脱涩,脱涩过程中果实硬度和可溶性固形物均呈缓慢下降的趋势;总单宁含量介于7.32 ~ 10.62 mg &;#8226; g-1FW之间;可溶性单宁含量、总酚含量及亲水性物质的ABTS自由基清除能力在前12 h下降明显,之后维持较低水平;亲脂性物质的ABTS清除能力在整个脱涩过程中变化不大且一直维持较低水平。其中,总酚含量与ABTS自由基清除能力呈极显著正相关。     

部分中国原产甜柿种质果实脱涩类型的鉴定

 以部分中国原产甜柿为试材, 通过对可溶性单宁含量测定和单宁细胞切片观察发现, 在果实接近成熟时, ‘罗田甜柿’、‘宝盖甜柿’、‘秋焰甜柿’ (鄂柿1号) 果肉中单宁细胞较小, 所占比例较低,可溶性单宁含量低于0.2%。因此确认供试中国甜柿种质属于完全甜柿。     

1-甲基环丙烯对‘富有’甜柿采后主要生理指标及细胞超微结构的影响

 以完全甜柿‘富有’ (Diospyros kaki L.‘Fuyu’) 为试材, 研究了在室温(20 ±2) ℃贮藏条件下1 - 甲基环丙烯(1-MCP) 0.50 μL·L^-1处理对果实的影响。结果表明: 1-MCP处理可显著抑制其呼吸速率、乙烯释放速率和衰老软化进程; 12MCP处理通过抑制果实中LOX活性的升高和MDA含量的积累,一定程度上维持了果肉细胞器和膜系统的完整性, 延缓甜柿果实的软化衰老进程。     

Physico-chemical changes during growth of persimmon fruits in the East Mediterranean climate region

Physico-chemical changes were monitored during growth of pollination variant non-astringent ‘Harbiye’ persimmon fruits (Diospyros kaki L.) grown at low or high altitude of the East Mediterranean Region of Turkey for two growing seasons (2001–2002 and 2002–2003). Fruit growth in diameter followed a typical double sigmoid curve, consisting of two rapid growth stages, stage I and stage III, separated by a period of slow growth (stage II) at both altitudes. The durations of stages I, II and III were 105–119, 21–35 and 21–42 days, respectively, at low and high altitude. ‘Harbiye’ persimmons showed significant decreases in soluble tannin concentration and total carotenoid content during stage I. At the end of stage I, ‘Harbiye’ persimmons became non-astringent. Stage II was characterized with slow growth, the beginning of acid degradation and a significant increase in total sugars, especially in the sucrose component. At end of stage II, the fruit began to turn yellow-orange, indicating the occurrence of colour break. The greatest increase in total soluble solids (TSS) content occurred in the final month before harvest during stage III when pronounced changes in skin colour and softening of fruits were observed. The 175 and 168 days after full bloom (DAFB) at low and high altitudes, respectively, are appropriate timing for harvest of the ‘Harbiye’ persimmon fruits in the East Mediterranean region. At these stages, ‘Harbiye’ persimmon fruits reached the best quality for consumers.     

Effects of CPPU on fruit set and fruit growth in Japanese persimmon

The effects of hand-pollination and spraying with N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) on fruit set and fruit growth of ‘Matsumoto-Wase-Fuyu’, which is a member of the pollination-constant, non-astringent group of persimmons (PCNA) were investigated. Staminate flowers of pollinizers in the orchard were eliminated before anthesis. Hand-pollination was carried out at full bloom (FB). Without prior hand-pollination, CPPU at 5 or 10 mg 1⁻¹ was sprayed 11 days after FB. Hand-pollination and spraying with CPPU increased fruit set before thinning of fruits by hand. The number of fruits after thinning did not differ among treatments. The yield of marketable fruits after hand-pollination was similar to that after treatment at 5 mg 1⁻¹, but was higher than that for untreated trees. Formation of a sunken fruit apex, which was observed in about 30% of fruits from untreated trees, was suppressed by application of CPPU. CPPU also delayed coloration of fruit. There were no differences among treatments in firmness or soluble solids concentrations of marketable fruits.     

中国甜柿遗传改良技术体系研究进展

在中国中部大别山区分布的中国原产完全甜柿(简称"中国甜柿"或CPCNA)及部分完全雄株是中国特有的柿属(Diospyros Linn.)资源,其与日本原产完全甜柿(简称"日本甜柿"或JPCNA)起源相对独立,且中国甜柿自然脱涩性状受显性单基因控制,因而在完全甜柿遗传改良中具有重大的利用价值。华中农业大学柿研究团队利用这两类种质与日本甜柿构成系列杂交组合,并将常规杂交与胚抢救培养、分子标记辅助自然脱涩性状和性别早期选择、嫩枝高位嫁接、圃地与产区同时评价等技术环节有机整合,建立了一套完全甜柿遗传改良技术体系。本文立足于该技术体系并参考国内外相关报道,对中国甜柿遗传改良工作的研究进展作一系统总结和综合评价,以期为中国的柿品种遗传改良提供科学依据。     

Fruit set and embryo rescue in crosses using parthenocarpic ‘Mopanshi’ persimmon

The ‘Mopanshi’ persimmon is a seedless, astringent parthenocarpic cultivar that does not produce male flowers. After pollination using four non-astringent cultivars (‘Zenjimaru’, ‘Nishimurawase’, ‘Okugosho’ and ‘Hanagosho’), seeds were produced to different degrees. ‘Mopanshi’ fruits pollinated with ‘Zenjimaru’ produced far more seeds than those pollinated with the other three cultivars. The ratio of abnormal seeds obtained from the fruits pollinated with ‘Hanagosho’ was higher than that obtained from the fruits pollinated with the other three cultivars. Most embryos degenerated in the early to late stages of seed development. Immature embryos were cultured in a modified MS medium (half of NO₃ in MS medium + 0.4 μM BA + 0.1 μM IBA) with the greatest success (52–80%) from embryos taken from fruits 60–80 days after pollination. Seedlings failed to initiate radicles so they were transferred to dark culture conditions for 8 days or to a rooting media that contained 3% sucrose and 1% Chinese ink. The seedlings on the medium darkened with ink rooted at greater than 90.83% compared to 75.83% for dark cultured seedlings. This study demonstrated that ‘Mopanshi’ persimmon could be used as a female parent in crosses, but embryos needed to be moved to tissue culture conditions to continue to develop and form plantlets.     

Phenolics concentration and antioxidant capacity of different fruit tissues of astringent versus non-astringent persimmons

Astringent and non-astringent persimmon fruits were compared for phenolic compounds, and their antioxidant capacity was studied in both peel and pulp. Fruits that were astringent generally had significantly higher concentrations of phenolics and greater capacities in either tissue. Pulp from astringent persimmons had more phenolics and higher capacity whereas the same was true for peels from non-astringent fruits. Among the methods tested for determining antioxidant capacity (ABTS, DPPH, FRAP, TBARS, SRSA, and HRSA), ABTS showed the best correlation with phenolics concentration while HRSA assays were not sufficiently sensitive to distinguish among genotypes or between fruit tissues. Therefore, we suggest that, for monitoring antioxidant capacity in persimmon, the ABTS method is most suitable.