Modified atmosphere packaging of minimally processed avocado cv. ‘Booth 7’

Summary

Avocado fruits were washed with 200 µg l^–1 active chlorine, partially ripened to a firmness of about 12.5 ± 0.6 kg cm^–2, and sliced. Fruit slices were dipped in 1.0 mg l^–1 citric acid and 200 µg l^–1 ascorbic acid maintained at 4°–6°C for 2 min, dried with tissue paper and packaged in 0.05 mm or 0.075 mm-thick low density polyethylene (LDPE) at a 1:1 surface area to product weight ratio (cm² g^–1). Sodium chloride (1 g) sealed in 0.075 mm-thick poly-coated paper pouches was included in the packages for moisture absorption. In-package O₂ and CO₂ concentrations, as well as the ethanol and acetaldehyde concentrations, firmness and lightness (L^* value) of the tissue slices were measured during storage for 10 d. The sensory attributes of the modified atmosphere (MA)-packaged slices were compared with fresh fruit slices. In-package O₂ concentrations fell from 14.1% to 6.3% and CO₂ concentrations rose from 4.7% to 4.9%. Ethanol concentrations increased from 9.0 to 32.1 µg g^–1 and acetaldehyde from 1.1 to 3.8 µg g^–1 during storage from day-1 to day-10 in the 0.05 mm-thick LDPE with sodium chloride moisture absorbers. In-package concentrations of O₂ fell from 10.8% to 3.8% and CO₂ rose from 3.8% to 8.1%, while ethanol concentrations increased from 10.0 to 40.4 µg g^–1 and acetaldehyde from 1.3 to 4.7 µg g^–1 during storage from day-1 to day-10 in the 0.075 mm-thick LDPE with sodium chloride moisture absorbers. The L^* value and sensory attributes of avocado slices packaged in 0.05 mm-thick LDPE, with moisture absorbers, were not significantly different from fresh slices, indicating the effectiveness of these MA conditions. Regardless of packaging conditions, avocado slices reached the firmness values of 5.8–6.3 kg cm^–2 required for the ‘table-ripe’ stage on day-10 in storage. Therefore, packaging of ‘Booth 7’ avocado slices in 0.05 mm-thick LDPE with sodium chloride as a moisture absorber resulted in a storage-life of 10 d at 8°C and 90 ± 2% RH.     

Shelf-life and quality of ber (Ziziphus mauritiana Lamk) fruits after postharvest water dipping treatments and storage

Summary

An experiment was conducted to study the effect of postharvest water dipping treatments and storage conditions on shelf life and quality of ber (Ziziphus mauritianaLamk). Fresh fruits of ber ‘Umran ’ were dipped in either cold (128C) or hot (50?C) water for 5 min and packed under different storage containers i.e. corrugated fibre board boxes, sealed polythene bags and perforated polythene bags. Control fruits were packed without dipping treatment. Result showed that postharvest water dipping at 508C for 5 min significantly increased the shelf life and maintained the quality of ber fruits, particularly late in the storage period. Fruits packed in sealed polythene bags significantly lowered the loss in fruit weight, spoilage and ripening with consequent increase in acidity and organoleptic score. Interactive results showed that hot-water treated fruits stored in modified atmospheric bags (sealed polythene bags) were qualitatively better than control fruits in terms of colour, taste and appearance. The organoleptic score reveals the acceptability of these fruits even after day 8 of storage. The control fruits were not found acceptable after day 4 of storage. It is suggested that postharvest fruit dipping in hot water (508C) forfive minutes followed by packaging in sealed polythene bags can enhance the shelf life and quality of ber fruits.     

Monitoring Blanching Induced Debittering and Storage Losses of Naringin in Orange Subjected to Osmotic Dehydration

Naringin, a bitter bioflavonoid of orange, widely reported for health promoting benefits is also responsible for reduced acceptability of many orange products where peels are integral components. The current study quantified naringin concentrations present in three types of oranges viz., Nagpur (Citrus reticulata Blanco), Kinnow (Citrus nobilis × Citrus deliciosa), and Mandarin (Citrus reticulata) spectrophotometrically and by high performance liquid chromatograph. The oranges were subjected to repeated blanching at a mild blanching temperature of 65 °C, subjected to osmodehydration and the loss of naringin monitored during processing as well as during extended storage of up to 6 months at room temperature. A wide range of physicochemical parameters were monitored at monthly intervals during the entire period of storage. Blanching reduced the naringin content by 50% and storage further decreased it to 3–10 mg/100g for all of the cultivars studied. In terms of physicochemical parameters and sensory analysis, Kinnow and Mandarin cultivars are better suited for osmotic dehydration.     

微孔膜包装对鸭梨贮藏品质的影响(英文)

鸭梨易受二氧化碳伤害。在目前的贮藏实践中,鸭梨不用保鲜膜包装而使用纸包裹(通常是硫酸纸)。但纸包裹的鸭梨失水严重,果皮很容易起皱,因而有必要开发更适合的贮藏方法。分别以常规LDPE(线性低密度聚乙烯)膜包装和硫酸纸包裹作为对照,研究微孔LDPE膜包装对鸭梨贮藏品质的影响。在整个贮藏过程中,常规LDPE袋中二氧化碳浓度在1.1%～3.2%,而微孔LDPE袋中二氧化碳体积分数在0～0.6%。微孔LDPE袋包装能降低鸭梨的果心、果肉褐变,减少失重和果皮起皱。不同处理的鸭梨总可溶性固形物(TSS)和可滴定酸含量(TA)没有明显差异。因此,采用微孔膜包装贮藏鸭梨比目前使用的纸包装贮藏具有明显的优势。     

Fruit set,seed development and embryo germination in interploid crosses of citrus

Interploid crosses of diploid Kinnow mandarin, Succari sweet orange and Sweet lime with tetraploid Kinnow were made reciprocally for the production of triploid plants. Low fruit set and occurrence of underdeveloped or empty seeds was common in all interploid crosses. The hybrid fruits harvested after 12–14 weeks or 7 months after pollination produced many underdeveloped and few developed seeds; however, tetraploid Kinnow as seed parent yielded more developed seeds per fruit. The under developed seeds were devoid of endosperm. Nucellar embryony was higher in the diploid than in the tetraploid strain of Kinnow. Immature embryos of seeds harvested 12–14 weeks after pollination were cultured in vitro on MS media supplemented with adenine sulphate (20 mg l⁻¹) and malt extract (500 mg l⁻¹). Maximum germination (75%) of hybrid embryos from underdeveloped seeds was obtained in 4× × 2× cross of Kinnow strains. The germinated plantlets were transferred into pots and noted 59–89.3% survival rate in various crosses.     

Modified atmosphere packaging of ‘Kolikuttu’ bananas at low temperature

Summary

Mature `Kolikuttu' bananas were packed under modified atmosphere (M.A.) conditions using low density polyethylene (LDPE) bags and stored at 14°C and 94% r.h. The effect of ethylene scavengers on storage life of banana was examined. The in-package concentrations of oxygen, carbon dioxide and ethylene were measured during storage. Percentage weight loss, changes in firmness, total soluble solids (TSS), pH and sugar: acid during storage were also determined. Based on the in-package gaseous composition, the optimum storage period was defined. After termination of storage, bananas were allowed to ripen naturally, and the physico-chemical properties of ripened banana were analysed. `Kolikuttu' bananas could be packed in LDPE (0.075 mm) and stored at 14°C and 94% r.h. for 24.d. Storage life could be further extended up to 30.d by using ethylene scavengers. Physico-chemical properties of M.A. stored banana after ripening were similar to those held under ambient conditions. Therefore, packaging of `Kolikuttu' banana as individual hands in LDPE (0.075.mm) bags of 1:1 surface to weight ratio (cm² g^-1) with 50 ml of saturated potassium permanganate absorbed onto suitable porous matrices could be recommended to increase storage lifeat 14°C.     

不同保鲜剂和包装材料对鲜切西芹保鲜效果研究

研究了过氧化氢、柠檬酸与氯化钙组合,以及不同包装材料高密度聚乙烯薄膜(HDPE)、普通聚乙烯薄膜(PE)及低密度聚乙烯薄膜(LDPE)对鲜切西芹的保鲜作用.试验结果表明,过氧化氢+柠檬酸+氯化钙组合时鲜切西芹有保鲜作用,可降低失重率,使呼吸代谢、相时电导率处于较低水平,鲜度指数也明显高于对照.LDPE,HDPE,PE三种包装材料对鲜切西芹的保鲜效果影响不明显.0.15%H2O2+0.1%CA+0.4%CaCl2组合对鲜切西芹的保鲜效果最好,贮藏9 d时,鲜度指数仍达到76.9%.     

不同包装处理对蓝浆果贮藏期间生理和贮藏性的影响

为了解引种到我国南方栽培的蓝浆果鲜果低温贮藏期间的生理变化状况,并为保鲜贮藏选择适宜的包装材料提供科学依据,研究了在2℃条件下,不同薄膜包装处理对蓝浆果果实贮藏期间可溶性固形物、维生素C、乙醛、乙醇、原果胶和花色苷的含量,以及呼吸强度、多聚半乳糖醛酸酶(PG)和果胶甲酯酶(PE)活性、失重率、腐烂率变化的影响。结果表明,薄膜包装对降低果实失重率和腐烂率具有较好的效果;对降低呼吸强度、抑制多聚半乳糖醛酸酶(PG)和果胶酯酶(PE)的活性以及花色苷含量的下降有一定效果;对减缓贮藏期间可溶性固形物、维生素C和原果胶含量的下降无明显影响。总体看来,0.08mm聚乙烯塑料薄膜(PE)袋适合作为贮藏30d的包装材料。     

Effect of storage temperature on ripening and quality of custard apple (Annona squamosa L.) fruits

Summary

The effect of storage temperature on ripening, shelf life and chemical composition of custard apple (Annona squamosa L.) fruits stored at 10,15,20 and 25°C was studied. The safe range of storage temperature was found to be between 15 and 20°C, with maximum shelf life at 15°C. The ripening of fruits was observed on days 4, 6 and 9 of storage at 25,20, and 15°C respectively. The colour of the pulp, texture, taste and flavour of ripe fruits held at 25 and 20°C were superior followed by fruits stored at 15°C. At 10°C, the fruits became hard with surface blackening, messy pulp and less sweetness. The major changes during ripening were a continuous decrease in fruit firmness and starch content and a continuous increase in TSS and sugars, the changes being more rapid at 25 and 20°C than at 15 and 10°C. The acidity and ascorbic acid contents increased slightly during the initial stages of ripening followed by a decline, in the fruits stored at different temperatures. Custard apple fruits stored at 25 and 20^CC had a clear climacteric peak whereas those stored at 15 and 10°C did not show any distinct rise in respiration rate. Ethylene peak (2.40 µl kg^–1 h^–1) coincided with the respiratory climacteric at 25^CC storage, corresponding with the peaks in TSS, sugars, ascorbic acid and acidity.     

不同消毒剂及清洗温度对番茄货架期腐烂率的影响

针对番茄采后腐烂率较高的问题,研究了不同清洗温度〔果温（28±5）℃〕下消毒剂（100  mg·kg^-1 NaClO和5 mg·kg^-1 ClO₂）和自来水清洗处理对番茄货架期（PE包装,室温28～30 ℃,7 d）腐 烂率的影响。结果表明,与不清洗对照相比,清洗后番茄果实腐烂率由47 %下降到9 %～26 %;清洗温度 对自来水和ClO₂处理的番茄果实腐烂率影响不大,但高于果温（28 ℃）5 ℃的NaClO处理的番茄果实腐 烂率较低于果温5 ℃的NaClO处理显著降低,其货架7 d番茄果实腐烂率仅为9 %,是各清洗处理中效果最 好的。     

间歇升温对冷藏桃果实游离脯氨酸含量和冷害的影响

观察分析了间歇升温对冷藏大久保桃果实游离脯氨酸含量、细胞膜透性及冷害的影响,结果表明:冷藏(2±1℃)30d及4d货架期(25—28℃)后,升温24h和36h的桃果实未发生冷害,脯氨酸含量在货架期下降;升温12h和对照的果实冷害严重,脯氨酸含量在货架期急剧上升,显著和极显著高于前两个处理,冷害越严重,值越大。细胞膜透性与冷害发生及严重程度无关,冷藏期间升温处理果实的膜透性大于对照,货架期结束时,各处理间无显著差异。     

Effects of Environment on Rubus Idaeus L. V. Dormancy and Flowering of the Mature Shoot

Further tests with a modified-atmosphere system using Ca(OH)₂ inserts in gas-proof plastic-lined bulk bins have shown that non-toxic concentrations of C0₂ and 0₂ can be maintained in these packages both in storage and in transit.

The value of this approach to the modified-atmosphere packaging of fruits and vegetables in relation to the dependence on gas-permeable films is briefly discussed.     

Quality of raisins under different packaging and storage conditions

We determined the effect of different storage systems and packaging on the quality of ‘Sultana Seedless’ raisins. The fruit were packed in plastic boxes and kept under controlled atmosphere (1% O₂ and 3% CO₂) at 0°C and 75–85% RH for 12 months (CA), packed in vacuum bags and kept under normal atmosphere (21% O₂–0.03% CO₂) (NA) and packed in thin plastic bags + carton boxes and kept under ambient condition (semi-refrigeration), at 0°C and 90% ± 5 RH for 12 months (AC). Fruit kept under CA or NA had acceptable fruit quality in terms of general appearance and taste for 10 months, whereas fruit quality was unacceptable at that time under AC. Fruit under NA had less weight loss than fruit under the other conditions. Differences in skin colour were relatively small, apart from the h° values. Concentrations of ochratoxin A were generally higher with AC. External appearance and taste were better with CA and NA. As a result, raisins can be stored for 10 months with good quality in vacuum package in NA (0°C and 90% ± 5 RH) and CA (1% O₂–3% CO₂) at 0°C and 75–85% RH.     

二氧化碳高渗透性膜包装对冬枣贮藏品质的影响

以二氧化碳高渗透性保鲜膜包装采后冬枣,以微孔保鲜膜作对照,研究了不同包装方式对冬枣保鲜袋内氧气和二氧化碳浓度、可溶性固形物(SSC)和维生素C(VC)含量、果肉乙醇和乙醛含量、果肉风味及好果率的影响。结果表明:2种包装袋内二氧化碳浓度相近,均低于0.5%的水平;微孔袋内氧气浓度接近于空气中氧含量,但二氧化碳高渗透性膜包装袋内氧气含量在3%～4%之间。二氧化碳高渗透性膜包装的冬枣可溶性固形物和维生素C含量高于微孔膜包装,但2种包装的冬枣的乙醇和乙醛含量相近。二氧化碳高渗透性膜包装的冬枣的风味和好果率明显高于微孔膜包装。     

不同光质膜对草莓果实品质的影响

 研究了相同光强下不同光质对‘丰香’草莓果实品质的影响。结果表明, 绿膜、中性膜、黄膜、蓝膜、红膜下生长的果实依次越来越红、越来越暗。果实色度值以红膜下的最大, 其次为中性膜处理,黄膜比中性膜处理略小但差异不显著, 绿膜处理最小, 这与不同膜透射的红橙光比例一致。不同膜处理的果实抗坏血酸含量高低与不同膜透射的紫外光和蓝紫光成分比例一致, 与红光/蓝光比值相反。红膜下的草莓产量最高、果实最大、着色最好, 蓝膜下的草莓果实含糖量、可溶性固形物含量、抗坏血酸含量和固酸比均最高, 绿膜下产量最低、果实最小、着色差且含糖量最低。     

几种机能性薄膜包装对香蕉贮藏效果的影响

 测定了4 种日本产机能性薄膜和聚乙烯薄膜在20 ℃的气体透过性,并用其分别包装经乙烯处理的香蕉,测定20 ℃贮藏期间袋内气体浓度、香蕉呼吸强度、乙烯释放量、果肉硬度与果皮色的变化。结果表明:机能性薄膜并不能有效地吸附去除包装内的乙烯气体;在一定温度下,薄膜的透气性是影响自发气调包装效果的主要因素。     

不同包装材料对生菜采后生理及保鲜效果的影响

为探索低温条件下适宜的包装材料,以5种不同包装材料PA/PE、OPP/CPP、HDPE、PE、PD961包装的生菜为研究对象,研究不同包装材料对生菜采后生理及保鲜效果的影响。结果表明:经过包装处理的生菜贮藏效果优于无包装组,其中HDPE包装材料较好地保持了叶用生菜的叶绿素含量和感官品质,延缓了呼吸高峰的出现、抑制PPO酶活性,贮藏效果最好。不同包装材料对生菜采后生理及保鲜效果存在明显差异,其效果依次为HDPEOPP/CPPPEPA/PEPD961。     

龙眼采后生理及贮藏保鲜

在一定范围内，龙眼果肉细胞透性越低，总糖、还原糖与可溶性固形物含量越高，果实品质风味越好。试验采取九成熟福眼果实测定其乙烯释放量只有２．３１－３．９１ｎｌ·ｇ~(-１)·ｈ~(-１)，乙烯作用不明显，不是果实主要衰老激素。果实采后没有明显呼吸高峰，不具跃变型水果典型特征，所以不适于气调贮藏，较适于冷藏。福眼果实采后用绿色Ⅰ和绿色Ⅱ保鲜剂洗果、ＥＶＡ薄膜袋包装，效果最佳；３０±２℃贮藏８ｄ好果率９６．６％，３－４℃贮藏４５ｄ好果率９８．８％；在－１８℃速冻贮藏１８３ｄ和３６６ｄ，好果率分别为９９．５％和９８．０％。     

The influence of gibberellic acid, 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine on fruit-set of Clementine mandarin

A study was made of the influences of gibberellic acid (GA₃), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA) on leafy inflorescences — and of GA₃ on entire trees — on fruit-set and fruit-weight of Clementine mandarin (Citrus reticulata Blanco).Applying GA₃ to inflorescences of cultivar ‘Fino’ (seedless Clementine) between anthesis and 14 days after anthesis increased fruit-set and weight of the fruits at harvest. No significant differences in effects were observed between the application to leaves, to flowers or to leaves and flowers simultaneously. GA₃ induced the development of parthenocarpic fruits of cultivar ‘Monreal’ (Clementine with seeds) and a fruit-set similar to that obtained with self-pollination. Spraying GA₃ (5–200 mg/l) to entire trees of cultivar ‘Fino’ increased the number of fruits per tree and decreased the average weight of the fruits. However, the commercial yield per tree increased with the concentration of GA₃ employed.The application of 2,4-D and BA to inflorescences of cultivar ‘Fino’ increased fruit-setting and weight of the fruits, although not as efficiently as GA₃, both the concentration and the time of application being more critical.     

不同包装和药剂处理对冬雪蜜桃贮藏性的影响

不同包装与药剂配合处理能较好地保持果实的硬度,贮藏１３周后各处理组合的果实硬度比对照果分别高２１．４％～５９．５％。药剂和包装处理对果实的可溶性固形物含量没有明显的影响。冬雪蜜桃果心褐变主要与果实的衰老有关,ＧＡ_３和钙处理明显地减少贮藏期间果心的褐变程度。