Effects of freezing preservation on mango (Mangifera indica,L.) peroxidase

This work describes the effects of freezing preservation on mango (cvs Lippens and Smith) peroxidase (E.C. 1.11.1.7); POD). Frozen mango slices showed lower levels of POD activity than raw fruits (17% cv Lippens; 50% cv Smith after 2 months storage time). A regeneration of this activity was found after 6 months of frozen storage. Regeneration continued to the end of the study (12 months) in both cultivars. During the whole period of storage, inactivation rates in Smith POD were higher than in Lippens. The isoenzymic pattern of Lippens POD showed four strongly anionic species that did not appear in the Smith pattern. The activity of these four bands is the most stable to low temperatures, and is the possible cause of the major resistence of Lippens peroxidase to freezing and frozen storage. Thus the Smith cultivar may be more suitable for freezing preservation.     

Effects of freezing preservation on mango (Mangifera indica, L.) peroxidase

This work describes the effects of freezing preservation on mango (cvs Lippens and Smith) peroxidase (E.C. 1.11.1.7); POD). Frozen mango slices showed lower levels of POD activity than raw fruits (17% cv Lippens; 50% cv Smith after 2 months storage time). A regeneration of this activity was found after 6 months of frozen storage. Regeneration continued to the end of the study (12 months) in both cultivars. During the whole period of storage, inactivation rates in Smith POD were higher than in Lippens. The isoenzymic pattern of Lippens POD showed four strongly anionic species that did not appear in the Smith pattern. The activity of these four bands is the most stable to low temperatures, and is the possible cause of the major resistence of Lippens peroxidase to freezing and frozen storage. Thus the Smith cultivar may be more suitable for freezing preservation.

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Einfluß der Gefrierlagerung auf die Aktivität der Mangoperoxidase (Mangifera indica, L.)

Zusammenfassung Diese Arbeit beschreibt die Auswirkungen der Gefrierlagerung auf die Peroxidase (E.C. 1.11.1.7) von Mangofrüchten, Sorte Lippens und Smith. Die gefrorenen Mangoscheiben wiesen niedrigere Peroxidasewerte auf als die rohen Früchte (um 17% geringer bei Lippens und um 50% bei Smith, nach zwei Monaten Lagerung). Eine Reaktivierung konnte nach sechs Monaten Tiefkühlung festgestellt werden. Diese Reaktivierung hielt bei beiden Mangosorten bis zum Ende der Untersuchung (also 12 Monate) an. Während der ganzen Lagerungszeit ließ die Inaktivierung der Peroxidase der Lippens vier stark anionische Formen erkennen, die bei der Sorte Smith nicht auftraten. Es stellte sich heraus, daß die Aktivität dieser vier Formen die größte Stabilität gegenüber tiefen Temperaturen aufweist. Wahrscheinlich ist das der Grund für die größere Widerstandsfähigkeit der Peroxidase der Sorte Lippens gegenüber Gefrieren und Tiefkühlung. Dieses Ergebnis weist auf eine bessere Eignung für die Gefrierkonservierung der Mangosorte Smith hin.

     

Freezing preservation of four Spanish mango cultivars (Mangifera indica L.): chemical and biochemical aspects

Summary Chemical and biochemical changes taking place during freezing and frozen storage of four Spanish mango cultivars: Smith, Lippens, Palmer and Davis-Haden were studied. Mango was air-blast-frozen as slices without any previous treatment and stored at –18 °C for a 4-month period. Freezing preservation of mango slices did not lead to changes in moisture content. The titrable acidity of the slices decreased as the pH increased in all cultivars due to the freezing process; no changes were found in these parameters throughout frozen storage. The behaviour of soluble solids and reducing and total sugar contents showed that no important changes appeared in the cultivars considered. Ascorbic acid and-carotene contents decreased considerably after 120 days frozen storage, being Davis-Haden the mango cultivar showing values of those parameters closest to the raw fruits. Peroxidase (POD; EC 1.11.1.7) and polyphenoloxidase (PPO; EC 1.14.18.1) activities slowed down after freezing, and no regeneration was found throughout frozen storage. The final PPO activity was low (<20% as compared to the raw fruit) whereas the POD activity was higher (>40% raw fruit). The remaining POD activity might cause deteriorative changes in the final quality of frozen mango slices.

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Gefrier-Konservierung von vier spanischen Mangosorten (Mangifera indica L.): Chemische und biochemische Aspekte

Zusammenfassung Es wurden die chemischen und biochemischen Veränderungen durch Tiefgefrieren und Gefrierlagerung von vier spanischen Mangosorten (Smith, Lippens, Palmer und Davis-Haden) untersucht. Die Mangos wurden in Scheiben ohne vorherige Behandlung im Luftstrom eingefroren und ohne Veränderung in der Restfeuchtigkeit bei –18 °C für vier Monate gelagert. Durch das Gefrieren sank bei allen Sorten der Gehalt an titrierbarer Säure und der pH-Wert stieg an, während sich bei der Gefrierlagerung keine weiteren Veränderungen ergaben. Keine signifikanten Veränderungen zeigten sich bei den Gehalten an löslichen und reduzierenden Substanzen und Gesamtzucker. Der Gehalt an Ascorbinsäure und-Carotin hatte nach 120 Tagen Gefrierlagerung erheblich abgenommen. Die Sorte Davis-Haden zeigte dabei den geringsten Unterschied zur frischen Frucht. Die Aktivität der Enzyme Peroxidase (POD; EC 1.11.1.7) und Polyphenoloxidase (PPO; EC 1.14.18.1) wurde durch das Gefrieren verringert und während der Gefrierlagerung wurde keine Reaktivierung beobachtet. Die PPO-Aktivität am Ende der Lagerung war niedrig (<20% der frischen Frucht), während die POD-Aktivität im Vergleich hÖher war (>40% der frischen Frucht). Die verbleibende Aktivität der POD könnte zu einem Qualitätsabfall in gefrorenen Mangoscheiben führen.

     

OXIDATIVE ENZYME ACTIVITIES AND SOLUBLE PROTEIN CONTENT IN LEAVES AND FRUITS OF OLIVES DURING RIPENING

Changes in the content and composition of soluble proteins and the activities of ionically bound peroxidase and polyphenoloxidase in leaves and fruits of olive trees Olea europaea cv. Zard from three regions during “on” and “off” years were evaluated. It was shown that peroxidase and polyphenoloxidase activities were low at early fruit developmental stages, gradually increased and were the highest at full fruit development (120–135 days after fruit set), and remained relatively high throughout ripening and softening stage. Polyacrylamide gel electrophoresis was used for characterization of peroxidase and polyphenoloxidase enzymes in leaf and fruit extracts. Isoenzymes were assessed in extracts from different regions and it was observed that some isoenzymes were only present at full fruit maturity. The protein content and its expression was estimated and characterized, and it was shown that protein content increased during various stages of fruit growth and remained the highest at full fruit ripening. The increase in enzyme activity from leaves and fruits was accompanied by differential expression of isoenzymes and the protein bands between 20 to 37 KDa, that seems to be a marker of full fruit maturity. It was also concluded that in all cases protein content and enzyme activities in leaves and fruits of olive trees during “on” years are considerably lower than those during “off” years.     

采后BTH处理对不同品种芒果果实防御酶活性影响

以“象牙”和“台农”芒果为试材,研究BTH 处理对2 个不同品种芒果果实中主要防御酶—— PAL、PPO 和POD 活性的影响,以探讨其增强不同果实抗病性的机理。结果表明：在整个贮藏过程中,“台农”果实本身3 种酶的活性均明显高于“象牙”果实;而经BTH 处理后,对2 个品种的芒果果实,均刺激了3 种酶活性的上升,并且“台农”果实上升幅度明显高于“象牙”果实。BTH 处理增强果实抗病性与刺激PAL、PPO 和POD 活性上升均有关系,并且对台农果实作用明显大于象牙果实。     

柠檬酸处理对采后芒果保鲜效果的影响

为探索芒果采后果实保鲜新方法,“台农一号”芒果采后分别经0(对照)、5、10mmol/L 柠檬酸浸果10min后,常温贮藏,定期检测果实的常规品质、成熟进程和病情发展的变化。结果表明：柠檬酸处理使果实软化、果肉可溶性固形物增加及可滴定酸含量降低的速率减缓,果实的转黄指数和病情指数降低,说明适当水平的柠檬酸处理能有效延缓芒果采后果实的成熟进程,并且抑制果实腐烂发生。柠檬酸处理是芒果采后贮藏保鲜的一种可选新方法。     

Limiting the deterioration of mango fruit during storage at room temperature by oxalate treatment

Effects of oxalate on the incidence of decay and ripening in mango fruit, and its physiological effects on the peel and flesh of mango were investigated after mango fruit (Mangifera indica L.) were dipped in different oxalate solutions for 10 min and then stored at 25 °C. Oxalate application decreased the incidence of decay and delayed the ripening process in mango fruit during storage. Potassium oxalate treatment resulted in increased activities of peroxidase (POD) in both the peel and the flesh and polyphenol oxidase (PPO) in the peel, without activation of phenylalanine ammonia-lyase activity, and elevated total phenolic content in the peel. The physiological effects of oxalate in increasing activities of POD and PPO and elevating total phenolic level could be involved in induced resistance of mango fruit against postharvest disease. Oxalate application could be a promising method to suppress postharvest deterioration and extend the useful shelf-life of mangoes.     

1-甲基环丙烯处理对采后甜瓜活性氧代谢的影响

研究1- 甲基环丙烯(1-MCP)处理对甜瓜(Cucuis melo L.ssp.melo pang)果实在贮藏过程中对其活性氧(reactive oxygen species,ROS)相关代谢的影响,在室温 (22～25℃)条件下,用1μL/L 1-MCP 处理早熟甜瓜“早黄蜜” 24h,贮藏于22℃,对果实中活性氧代谢的相关酶：超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性及超氧阴离子(O2 － ·)和丙二醛(MDA)含量进行测定。结果表明：1-MCP 处理抑制了甜瓜果实CAT 活性的下降,贮藏前期提高了SOD 活性,促进POD 活性迅速升高,并使其在第4 天达到峰值,贮藏过程高于对照果实。1-MCP 处理可显著降低果实中O2 － ·的产生速率,抑制MDA 的产生,延缓甜瓜果实采后衰老。     

1-MCP及其结构相似物处理对番茄采后贮藏效果的影响

为了研究环丙烯类乙烯抑制剂的作用效果,以绿熟期番茄为试材,用1-甲基环丙烯(1-MCP)、1-戊基环丙烯(1-PentCP)、1-辛基环丙烯(1-OCP)处理后,常温(18℃±2℃)贮藏,每隔3 d测定1次理化指标,研究三者对番茄果实后熟衰老和贮藏效果的影响。结果表明:1-MCP及其结构相似物处理番茄不同程度地降低了呼吸强度和乙烯释放量的峰值,抑制了番茄果实硬度的下降,延缓了可溶性固形物含量的上升,同时也有效抑制了后熟期番茄果实过氧化氢酶(CAT)活性、过氧化物酶(POD)活性,延缓了果实的后熟衰老。3种试验的抑制剂中,1-MCP、1-PentCP和1-OCP处理随支链长度的增加,抑制后熟衰老的效果依次降低。     

成熟度对芒果果实挥发物的影响

选用不同成熟度的海南小芒果为原料,以固相微萃取(SPME)技术为香气富集方法,气相色谱- 质谱联用(GC-MS)分析研究成熟度对芒果果实挥发物种类及其相对含量的影响。结果表明：芒果香气成分丰富,共检出56种香气成分,分为萜烯类、烃类、醛类、酮类、醇类、酯类6 类,其中萜烯类是主要成分,其随成熟度增加 而在果皮与果肉中相对含量降低,在半熟时最低,其中单萜相对含量大于倍半萜。果皮与果肉中酯类在绿熟时已经形成,并且在半熟时相对含量最高;随成熟度的增加果皮中醇类相对含量增大,但果肉中醇类则是在半熟时高度积累;醛类在果皮与果肉积累的成熟度不一样,分别是成熟和半熟;烃在果肉中逐渐降低,却在半熟果皮中含量最高。大多数芒果挥发物在半熟时形成,在此时对芒果果实进行调控,对提高芒果香气品质具有重要意义。     

Spatial and temporal changes in the volatile profile of Alphonso mango upon exogenous ethylene treatment

Alphonso is a highly favoured and exported mango cultivar among the vast mango germplasm of India. Being a climacteric fruit, ethylene plays an important role in ripening of mango. For deeper understanding of effect of pre-climacteric ethylene treatment on volatile profiles of Alphonso mango, 26 volatiles were tracked through six ripening stages of pulp and skin of ethylene-treated and control Alphonso fruits. The study revealed accelerated ripening in terms of early appearance of ripening-specific compounds, lactones and mesifuran, upon ethylene treatment. While the level of lactones remained unaffected, the mesifuran level vastly increased upon ethylene treatment. Skin showed high terpene content while pulp had higher amount of lactones compared to skin. This work points towards involvement of ethylene as a natural hormone in the biosynthesis of lactones and furanones in naturally ripened fruits; whereas, an increase in the terpene level during ripening appears to be independent of ethylene.     

Geographic variation in the flavour volatiles of Alphonso mango

Alphonso, one of the most popular cultivars of mango in India is known to exhibit geographic variation in the flavour of ripe fruits. To get chemical insight into this difference, volatiles were studied in the ripening fruits of Alphonso mangoes from three cultivation locations in India. Ripe fruits from Deogad had lower content of mono- and sesquiterpenes and higher content of lactones and furanones as compared to the fruits from Dapoli; whereas fruits from Vengurle had average quantities of these chemicals in comparison with Deogad and Dapoli fruits. This variation was clearly reflected as separate clustering of the localities in the Principal Component Analysis. The localities were indistinguishable from each other in terms of raw fruit volatiles. This study exemplifies a case of phenotypic plasticity; since the plants chosen were clonally propagated, such geographic variation in the volatiles can be attributed to varied abiotic conditions at these three localities.     

采后催熟对‘台农一号’芒果理化品质及营养特性的影响

采用外源乙烯利对‘台农一号’芒果进行催熟，乙烯利添加量0.1(w/w)，温度30℃，湿度40%～50%。探讨不同催熟阶段对芒果理化指标（硬度、色泽、可滴定酸、可溶性固形物），营养成分（类胡萝卜素、维生素C、可溶性蛋白质、总糖）和香气成分的影响。结果表明，在催熟过程中果实硬度从19.76 N下降到0.99 N，可滴定酸从1.37%下降至0.27%，而可溶性固形物从12.92%上升至23.64%。当催熟时间从0 h增加至60 h，黄色指数值显著（P<0.05）增加，约85%以上的果皮颜色转为黄色，类胡萝卜素含量可升高至4.90μg/g，维生素C从326.66 mg/100 g下降至180.00 mg/100 g，而总糖含量显著（P<0.05）增加；继续延长催熟时间至108 h，类胡萝卜素升高至10.93μg/g；维生素C、可溶性蛋白质和总糖等变化不显著。芒果果实香气物质主要是萜烯类化合物，其中异松油烯含量最高，在催熟60 h之内其含量迅速增大，外源乙烯利加快了果实中异松油烯的合成速率。综合评价催熟后果实理化及品质特性60 h后芒果色泽、香气等指标基本达到成熟。     

Mango (Mangifera indica L.), “The King of Fruits”—An Overview

Mango (Mangifera indica L.) is commercially the most important fruit crop of India, accounting for > 54% of the total mango produced worldwide. Over 30 different varieties of mango are grown, the most important one is Alphonso, which is rated best in the world. It is known for its strong aroma, intense peel coloration, delicious taste, and high nutritive value (due to its high content of vitamin C, β-carotene and minerals). The chemical composition of mango pulp varies with the location of cultivation, variety, and stage of maturity. There is an increase from 1 to 14% in the starch content during fruit development, and towards the end of maturity, both reducing and non-reducing sugars are found to be increasing. The fruit ripening process involves a series of physiological, biochemical, and organoleptic changes that lead to the development of a soft, edible, ripe fruit with desirable qualities. Ethylene, a plant growth hormone, regulates many aspects of fruit development and cell metabolism, including initiation of ripening and senescence, particularly in climacteric fruits. Textural softening, an integral part of ripening of almost all fruits, is a major quality attribute that determines consumer acceptance. Fruit softening is thus accompanied by molecular-structural changes in cell wall constituents, which have been studied at both substrate (polysaccharides) and enzyme (glycanases and glycosidases) levels. Several lines of evidence have enumerated on compositional and structural modifications in pectic and hemicellulosic polysaccharides, especially of xyloglucan-type polymers during mango fruit ripening. Of late, modern biotechnological approaches are paving the way for healthy propagation and rapid multiplication of valuable geno types and improved plants, which augment advantages such as non-seasonal, almost year-round production and conservation of germplasm for better international exchange. Somatic hybridization via protoplast fusion could be an alternative to overcome problems such as difficulties in establishing aseptic mango cultures from mature explants associated with phenolic browning. In this direction, further biotechnological approaches may be worth pursuing for sustained mango cultivation.     

Bioactivity of mango flesh and peel extracts on peroxisome proliferator-activated receptor γ [PPARγ] activation and MCF-7 cell proliferation: fraction and fruit variability

Mangos are a source of bioactive compounds with potential health promoting activity. Biological activities associated with mango fractions were assessed in cell-based assays to develop effective extraction and fractionation methodologies and to define sources of variability. Two techniques were developed for extraction and fractionation of mango fruit peel and flesh. Liquid chromatography-mass spectrometry (LC-MS) was used to assess compositional differences between mango fractions in flesh extracts. Many of the extracts were effective in inhibiting the proliferation of human breast cancer cells in vitro. All fractions showed bioactivity in PPAR activation assays, but quantitative responses showed marked fruit-to-fruit variability, highlighting the need to bulk fruit prior to extraction for activity-guided fractionation of bioactive components. This study also suggests that combinations of diverse molecular components may be responsible for cell-level bioactivities from mango fractions, and that purification and activity profiling of individual components may be difficult to relate to whole fruit effects. Practical Application: Although the health benefits of fruits are strongly indicated from studies of diet and disease, it is not known what role individual fruit types can play, particularly for tropical fruits. This study shows that there is a diversity of potentially beneficial bioactivities within the flesh and peel of mango fruit, although fruit-to-fruit variation can be large. The results add to the evidence that the food approach of eating all components of fruits is likely to be more beneficial to health than consuming refined extracts, as the purification process would inevitably remove components with beneficial bioactivities.     

套袋对芒果果实采后品质和后熟的影响

在芒果(Mangifera indica L.cv.Zihua)的生长期内,分别用纸袋和无纺布袋进行套袋处理,以不套袋果实作为对照。果实采收后于20℃,85%～95%RH的环境下进行贮藏,并定期取样进行观察测定。结果表明,生长期套袋的"紫花"芒果果实果面的锈斑发生率和锈斑指数都比对照果实低,套袋对芒果果实的可溶性固形物和可滴定酸含量、硬度、呼吸强度几乎没有影响,但套袋处理更容易使果实着色。布袋的效果优于纸袋。     

A study of peroxidase and amylase isoenzymes in different radish cultivars during winter storage

The changes in activities of soluble peroxidase (EC 1.11.1.7; POD) and amylase (EC 3.2.1.1) and in levels of soluble protein and reducing sugar are investigated in three cultivars of radishes (Raphanus Sativus L) in winter storage for 150 days. It has been shown that the activity of peroxidase increases at first and then decreases during the storage. The highest POD activity appears on the 90th day. The levels of reducing sugars change similarly. Peroxidase isoenzymes (types and activities) in these radish cultivars are obviously different during the storage. The highest activities of peroxidase isoenzymes are observed in Xinlimei (XLM) and the lowest in Dihuangying (DHY). The difference between the radish cultivars is also observed in the peroxidase isoenzyme types. Both cationic and anionic peroxidase isoenzymes appear in the radish during storage. The activities and PAGE bands of the amylase isoenzymes decrease with increasing storage time. The activities of amylase are the lowest in the XLM but highest in the DHY. A similar change is found for the levels of soluble protein during the storage: the levels are highest in XLM and lowest in DHY. These results suggest a possible correlation between the activity of peroxidase and the level of reducing sugar during storage. © 2000 Society of Chemical Industry     

不同溶质型桃果实成熟过程中酚类代谢与抗氧化能力的研究

以不同溶质型桃果实"加纳岩"和"雨花三号"为试材,测定两个品种桃果实在树体成熟过程中的多酚含量、类黄酮含量以及苯丙氨酸解氨酶(phenylalanin ammonialyase,PAL)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活性变化,并采用1,1-二苯基-2-三硝基苯肼(DPPH)法及2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)法对其抗氧化能力进行评价。结果表明:"加纳岩"桃果实的多酚含量和类黄酮含量在成熟过程中均显著高于"雨花三号"桃果实;软溶质型"雨花三号"桃PPO活力高于硬溶质型"加纳岩"桃,但前者POD及PAL活力低于后者,其中"加纳岩"桃PAL活力初期高,成熟过程中与多酚含量呈正相关,"雨花三号"桃PAL活力呈上升趋势,与多酚含量无显著相关性;DPPH法和ABTS法均表明"加纳岩"桃抗氧化能力高于"雨花三号"桃。     

1-MCP处理对冷藏番荔枝果实贮藏品质和生理变化的影响

以“非洲骄傲”番荔枝果实为试材,研究了1-MCP(1-甲基环丙烯)处理对冷藏(15℃)番荔枝果实贮藏效果和生理变化的影响。结果表明:1.8μl/L1-MCP处理能显著提高番荔枝的好果率,延缓番荔枝贮藏前期TSS含量的上升,推迟其成熟软化进程;1-MCP处理还能显著抑制番荔枝果实VC含量的下降(p<0.01),提高果实贮藏后期SOD、POD和CAT的活性;同时,1-MCP处理抑制了果实中PPO活性的升高和MDA含量的积累。