Efficacy of Artabotrys odoratissimus oil as a plant based antimicrobial against storage fungi and aflatoxin B1 secretion

The essential oil of Artabotrys odoratissimus R.Br. was evaluated for antifungal activity against some storage fungi causing contamination of food stuffs. Minimum inhibitory concentration of the oil was found to be 750 μL L⁻¹ against Aspergillus flavus Link. It was found superior over different prevalent synthetic fungicides which inhibited the growth of A. flavus between 1000–5000 μL L⁻¹. The oil exhibited broad fungitoxic spectrum against fourteen different storage fungi. Aspergillus fumigatus was inhibited at 1000 μL L⁻¹ whereas Cladosporium cladosporioides , Curvularia lunata , Fusarium oxysporum , Helminthosporium oryzae , Macrophomina phaseolina , Microsporum gypseum , Mucor racemosus , Penicillium italicum , Pythium debaryanum , Rhizoctonia solani , Sclerotium rolfsii and Trichoderma viride at 500 μL L⁻¹. Aspergillus niger was found to be inhibited only 84.9% at 1000 μL L⁻¹. In addition, the oil showed significant efficacy in arresting aflatoxin B₁ secretion by the toxigenic strain (Navjot 4NSt) of A. flavus at 750 μL L⁻¹. The efficacy of A. odoratissimus oil as aflatoxin suppressor is being reported for the first time.     

QUALITY CHANGES OF "SHIRO" YELLOW PLUMS IN RESPONSE TO TREATMENT WITH 1-METHYLCYCLOPROPENE

The overall objective of this study was to assess the effects of 1-methylcyclopropene (1-MCP) on the quality of yellow "Shiro" plums. During 2 years of study, plums were harvested from commercial orchards and exposed to 1 µL/L of 1-MCP for 24 h at 0C. Following treatment, the fruit were held at 0C for 0, 2 or 4 weeks and then evaluated for quality during a 2-week ripening period at 22C. In general, plums treated with 1-MCP were firmer, had higher soluble solids concentration (SSC) and retained more green color than non-treated fruits. The effect of 1-MCP on firmness was greater in plums from earlier harvests and in those stored for 4 weeks at 0C. 1-MCP treatment also reduced CO₂ production, ethylene and hydrophobic total volatiles in "Shiro" plums but these effects were reduced or lost with longer storage time.

PRACTICAL APPLICATIONS

The use of 1-MCP could be beneficial for extending the marketing window of "Shiro" plums, since firmness retention is improved and the color change from green to yellow is delayed. The limited effect of 1-MCP on CO₂ and ethylene production may be advantageous in that these are delayed and not completely inhibited. In climacteric fruits such as plum, the limited period of 1-MCP effectiveness could be a benefit when successful 1-MCP application requires a delay, rather than irretrievable inhibition of the ripening processes, which reduces marketability.     

Postharvest Aloe vera gel-coating modulates fruit ripening and quality of 'Arctic Snow' nectarine kept in ambient and cold storage

To evaluate the role of Aloe vera gel coating on ripening and fruit quality of nectarine ( Prunus persica L. Batch cv 'Arctic Snow'), the uncoated and coated fruit were allowed to ripen at 20 ± 1 °C in first experiment and in the second experiment, the fruit were stored at 0 ± 0.5 °C and 90 ± 5% RH for 3 and 6 weeks prior to ripening at 20 ± 1 °C. Aloe vera gel-coated fruit kept at ambient or 3 and 6 weeks cold storage reduced respiration rate, ethylene production (62, 37 and 43% respectively), retarded fruit softening, reduced electrolyte leakage (EL), weight loss (65%), levels of ascorbic acid and total antioxidants (24, 9 and 13%) during ripening than control. In conclusion, Aloe vera gel can be used for extending storage life at ambient or cold storage and maintaining quality of 'Arctic Snow' nectarine.     

1-甲基环丙烯在西兰花贮藏保鲜中的应用研究进展

西兰花属于呼吸跃变型花菜类蔬菜,对乙烯敏感,采后花蕾极易开放萎蔫、黄化和腐烂。1-甲基环丙烯(1-methylcyclopropene,1-MCP)是一种乙烯作用抑制剂,在果蔬采后贮藏保鲜中得到了广泛应用并取得了显著效果。该文查阅国内外有关1-MCP在西兰花贮藏保鲜中的研究,分析归纳1-MCP的作用机理和经过1-MCP单独处理后西兰花的呼吸代谢强度、果蔬品质、乙烯合成速率及各种酶活性的变化规律,以及1-MCP处理结合其他贮藏保鲜方法在西兰花贮藏保鲜中的应用情况,以期为1-MCP在西兰花贮藏保鲜中的应用和研究提供参考。     

1-MCP和预贮对深州蜜桃采后生理和品质的影响

为保持深州蜜桃冷藏期间良好的品质, 延长贮藏时间, 采用1 . 0 μ L / L 1 - 甲基环丙烯
（1-methylcyclopropene,1-MCP）熏蒸和预贮（8 ℃、5 d转入0 ℃）的方法对采后深州蜜桃进行处理,测定0 ℃冷
藏期间果实呼吸速率、乙烯释放速率和品质的变化。结果表明,1-MCP处理能够明显抑制桃果实冷藏期间的呼吸速
率和乙烯释放速率,推迟呼吸高峰期的出现;同时延缓了果实软化,抑制可溶性固形物含量上升,降低了果实的褐
变指数和腐烂指数;预贮促进了果实后熟,但预贮和1-MCP处理均明显降低了贮藏期果实褐变度和酚类物质含量,
二者结合处理对抑制果实褐变效果最佳。     

Pre‐ or post‐harvest applications of putrescine and low temperature storage affect fruit ripening and quality of ‘Angelino’ plum

BACKGROUND: Plum has a very short storage life. The role of pre‐ or post‐harvest applications of putrescine (PUT) and low temperature storage on fruit ripening and quality was investigated in plum fruit (Prunus salicina Lindl. cv. Angelino). RESULTS: Pre‐ or post‐harvest PUT treatments [(0.1, 1.0 or 2.0 mmol L^?1) + 0.01% Tween‐20 as a surfactant] delayed and suppressed the climacteric ethylene production and respiration rate irrespective of the method used to apply PUT. PUT‐treated fruit following low temperature storage (0 ± 1 °C; 90 ± 5% RH), at the ripe stage exhibited higher fruit firmness and titratable acidity (TA), while soluble solids content (SSC), levels of ascorbic acid, total carotenoids and total antioxidants were lower than in untreated fruit. Fruit both sprayed with PUT and stored in low temperature for 6 weeks, at the ripe stage showed reduced respiration rate, delayed changes in the SSC:TA ratio and levels of total carotenoids compared to post‐harvest PUT application. CONCLUSION: Pre‐harvest application of 2.0 mmol L^?1 PUT 1 week before the anticipated commercial harvest was more effective in delaying plum fruit ripening and can be used to extend the storage (0 ± 1 °C) life of plums for up to 6 weeks with minimum losses in fruit quality. Copyright © 2008 Society of Chemical Industry     

1-Methylcyclopropene Counteracts Ethylene-Induced Microbial Growth on Fresh-Cut Watermelon

ABSTRACT:  The effects of exogenous ethylene, 1-methylcyclopropene (1-MCP), or both on microbial growth on watermelon fruit and watermelon slices were investigated. Freshly harvested seedless watermelons ( Citrullus lanatus , cv. Sugar Heart) were treated with 0.5 or 1.0 ppm 1-MCP, 10 ppm ethylene, 1-MCP + ethylene, or left untreated as controls. Fruits were processed into wedge-shaped slices, packaged into rigid trays sealed with a polyethylene film with a 29.2 pmol s⁻¹ m⁻² Pa⁻¹ oxygen transmission rate. The slices were evaluated after 0-, 6-, and 12-d storage at 5 °C. Ethylene treatment alone increased the populations of aerobic bacteria, lactic acid bacteria, and yeasts and molds on the packaged slices during storage compared to those on corresponding control slices and resulted in extensive juice leakage from the slices. The ethylene treatment also resulted in high aerobic bacterial counts throughout the flesh of whole melons compared to the controls. Treating watermelons with 0.5 or 1.0 ppm 1-MCP prior to ethylene exposure counteracted the deleterious effects of ethylene. Extending the time from harvest to 1-MCP treatment increased the population of aerobic bacteria, but had no detectable effect on the growth of lactic acid bacteria or yeasts and molds. The results indicate that low concentrations (0.5 or 1.0 ppm) of 1-MCP can be used on whole watermelon to avoid deleterious effects of exogenous ethylene to which the melons could be exposed during shipping or storage.     

1-MCP应用于芒果贮藏保鲜的研究进展

呼吸跃变型水果芒果对乙烯非常敏感。1-MCP是一种有效的乙烯作用抑制剂,它能抑制乙烯所诱导的与果实后熟相关的一系列生理生化反应,进而延缓采后呼吸跃变型果实的衰老进程,保持果实的贮藏品质。综述了1-MCP的作用机理及1-MCP对采后芒果的呼吸速率、乙烯产量、果实品质及生理病害等生理生化指标的研究现状,同时介绍了1-MCP结构类似物以及1-MCP结合其他保鲜方法的应用情况,并对1-MCP应用前景进行了展望,以期为1-MCP在芒果贮藏保鲜中的应用和研究提供参考。     

Composition, sensory quality and respiration during ripening and storage of edible wild mango (Irvingia gabonensis)

The effects of tree and room ripening and of storage at chill temperatures and at 26–29°C on the sensory quality, composition and respiration of edible wild mango fruits were investigated.
Fruits harvested at the mature green stage and ripened at 26–29°C were slightly preferred to tree-ripened fruits in colour and texture. Apart from a lower moisture content, room-ripened fruits were comparable in composition with tree-ripened fruits. During storage at 26–29°C, CO₂ production increased sharply from 22 ml kg^-1 h^-1 at the end of the first day, reaching a maximum of 91 ml kg^-1 on day 5 and declining thereafter; O₂ consumption followed a similar trend. The respiratory climacteric coincided with the onset of ripening. Fruits held at 12–15°C developed symptoms of chilling injury including pitting and black spots in mature green fruits, and brownish discoloration, pitting, surface scald, excessive softening and decay in ripe fruits.     

Optimisation of the medium composition for production of protease and soybean peptides by Bacillus subtilis SHZ using response surface methodology

Responses surface methodology was employed to enhance the production of protease and soybean peptides by Bacillus subtilis SHZ. For screening of medium composition significantly influencing protease and soybean peptides yield, the two-level Plackett–Burman design was used. Among thirteen variables tested; KH₂PO₄, glucose and defatted soybean flour (DSF) were selected based on their high significant effect on both protease activity and soybean peptides yield. Then, a three-level Box–Behnken design was employed to optimise the medium composition for the production of the protease and soybean peptides in submerged fermentation. Mathematical models were then developed to show the effect of each medium composition and their interactions on the production of protease and soybean peptides. The model estimated that, the maximal protease activity (320 ± 1 U mL⁻¹) could be obtained when the concentrations of glucose, KH₂PO₄, DSF were set at 8–9 g L⁻¹, 2–3 g L⁻¹, 55–65 g L⁻¹, respectively; while a maximal yield of soybean peptides (8.5 ± 0.1 g L⁻¹) could be achieved when the concentrations of glucose, KH₂PO₄, DSF were set at 7–9 g L⁻¹, 3–4 g L⁻¹ and 55–58 g L⁻¹, respectively. These predicted values were also verified by validation experiments.     

1-MCP Preserves the Firmness of Stored Persimmon 'Rojo Brillante'

ABSTRACT: We studied the effects of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, on quality of persimmon cv.'Rojo Brillante.'Two assays were carried out, applying deastringency treatment before or after storage at 15 °C. In both experiments, fruit was treated with 0 (control), 0.5, or 1 μL/L of 1-MCP after harvest. Additionally, the effect of 2 applications of 0.5 μ L/L, one after harvest and the 2nd after a storage period, was evaluated. In all experiments, 1-MCP delayed softening and color evolution of persimmons. Ethanol and acetaldehyde levels in treated fruit were lower than those in control fruit. 1-MCP had no effects on weight loss, °Brix, or ethylene and CO₂ production.     

1-MCP对不同采收期黄冠梨褐心病及贮藏品质的影响

以黄冠梨果实为试材,研究1-甲基环丙烯(1-MCP)处理对不同采收期黄冠梨常温贮藏褐心病发生的控制效果及相关品质指标变化。结果表明:1-MCP处理能显著抑制黄冠梨常温贮藏期间果心褐变的发生,降低果实贮藏期间的呼吸速率,抑制乙烯释放速率,推迟乙烯释放高峰出现的时间,保持较好的果实硬度,延缓果实可滴定酸、可溶性固形物含量的下降,较好地保持黄冠梨果实的品质,保鲜效果显著。且1-MCP对黄冠梨褐心的控制效果与成熟度密切相关。     

The effect of storage at tropical ambient temperature on the quality and shelf life of grouper (Plectropomus maculatus)

Groupers ( Plectropomus maculatus ) were harvested from holding tanks and stored in ice until assessment rated them unacceptable. Groupers were also subjected to periods (2–12 h) of storage at tropical ambient (29–31 °C) immediately after harvest but prior to cooling in ice. The storage life of grouper stored continuously in ice was 18 days. A 2-h delay before cooling in ice approximately halves the storage life and for every further hour of malstorage the shelf-life was further reduced by approximately 1 day. The total volatile basic nitrogen (TVBN) and hypoxanthine contents were found to be good indicators of freshness in groupers, which were only acceptable with contents <31 mg N 100 per g and <2.0 μmoles g^–1, respectively and all unacceptable at >37 mg N 100 per g and 2.3 μmoles g^–1 respectively. TMA-N was found not be a reliable indicator of freshness.     

不同处理对磨盘柿冷藏及货架期品质与生理的影响

以磨盘柿为试材,用浓度为1.0 μL/L的1-MCP处理,用高浓度CO2(85%~90%)处理24 h,探究不同处理方式(CO2脱涩、1-MCP处理后CO2脱涩、1-MCP与CO2脱涩同时处理)对冷藏及冷藏后货架期果实的品质与生理影响。结果表明,与CO2脱涩相比较,1-MCP处理后CO2脱涩可以有效降低柿果呼吸强度,抑制乙烯生成速率、柿果色泽的改变,延缓柿果质地的降低,维持果实营养物质(TSS、TA及Vc含量)在较高水平,有效减缓了挥发性香气成分的减弱。但1-MCP与CO2脱涩同时处理却加速了果实成熟且贮藏后期差异显著(P<0.05)。因此,柿果经1-MCP处理后再高浓度CO2脱涩不仅可脱涩还具有较好的保鲜效果。     

Quality improvement and extension of shelf life by 1-methylcyclopropene in plum as affected by ripening stage at harvest

Plum (Prunus domestica L. cv. ‘President’) fruits were harvested at two pre-climacteric stages of ripeness (stage 1 and stage 2), and then treated with 1-methylcyclopropene (1-MCP) at two doses (0.3 and 0.5 μl l⁻¹) followed by 1, 2, 3, 4 and 5 weeks of cold storage and their respective 7 days of shelf life at 20 °C. Both 1-MCP doses were effective in terms of ethylene inhibition during shelf life after cold storage, for both ripening stages. Similarly, lower weight losses, delayed colour changes, reduced softening rate and diminished ripening index were found in 1-MCP treated plums than in controls at both stages of ripeness. Hence, during cold storage and shelf life, the efficacy of 1-MCP on ethylene production, weight loss, pulp firmness and ripening index was dose-dependent, while for colour and respiration rate the dose-dependence was only found during shelf life. The storability of 1-MCP treated plums could be extended up to 4 weeks of cold storage plus 7 days at 20 °C, and only up to 1 week of cold storage plus 7 days at 20 °C for controls. Then, 1-MCP is an effective tool for quality improvement and extension of shelf life in plums, and fruit might be harvested in stage 2 of ripening, at which the most desirable organoleptic attributes had been developed on tree.     

Effects of 1-MCP on chlorophyll degradation pathway-associated genes expression and chloroplast ultrastructure during the peel yellowing of Chinese pear fruits in storage

The peel yellowing is an important pigment physiological process of green fruit ripening, which mainly results from chlorophyll degradation in the fruit peel. In this work, two typical cultivars with different ripening speed, a slow ripening pear 'Emerald' (Pyrus bretschneideri Rehd. cv. Emerald) and a fast ripening 'Jingbai' (Pyrus ussuriensis Maxim. cv. Jingbai) were used to investigate the molecular mechanism of chlorophyll degradation in pear yellowing/ripening during postharvest storage. The fruits after harvest were treated with 1-methylcyclopropene (1-MCP), an ethylene action inhibitor at 1.0 μLl(-1) to determine its effect on chloroplast ultrastructure and the expression of chlorophyll degradation associated genes in peel tissues. Our results show that the pears treated with 1-MCP had a lower ethylene production rate and higher chlorophyll content compared to those of untreated fruit. The more intact chloroplasts with well-organised grana thylakoids and small plastoglobuli were maintained in the peel of 1-MCP treated fruit for up to 30 and 15 d in 'Emerald' and 'Jingbai', respectively. The expression of chlorophyll degradation associated genes: pheophorbide a oxygenase (PAO), non-yellow colouring (NYC), NYC1-like (NOL), stay-green 1(SGR1), was suppressed, while no significant change was found in chlorophyllase 1 (CHL1) and red chlorophyll catabolite reductase (RCCR) in both cultivar fruits treated with 1-MCP. These results suggest that 1-MCP can delay chlorophyll degradation by inhibiting ethylene production and suppressing the gene expression of PAO, NYC, NOL and SGR1, which are closely associated with chlorophyll catabolic pathway.     

The influence of enzymatic treatment of mash on the analytical composition of apple juice

Five apple juices were produced on a pilot scale by crushing the fruit, treating the mash with pectolytic enzymes, pressing, extracting water from the pomace, pasteurization, treatment of the juice with enzymes, combined gelatin/silica sol fining and final ultrafiltration. The temperature of the mash treatment was either ambient or one of 30, 40, 50 or 60 °C, in order to test whether this led to different compositional changes in the corresponding juices. The main emphasis was put on detection of D -galacturonic acid as the indicator substance for the extent of the enzymatic treatment. In the pasteurized raw juices after pressing we found values from 226 to 398 mg L⁻¹. A distinct increase of the galacturonic acid levels could be observed during the clarification steps. Enzymatic juice treatment raised the concentrations to 580–720 mg L⁻¹. After ultrafiltration, final values of 790–1100 mg L⁻¹ were measured. Generally, the highest values were found in the 50 °C sample, which is the optimum temperature for pectinase activity. This was also true for the colloid concentrations and polyphenols. The influence of the temperature of the enzymatic mash treatment on other characteristic juice parameters like total titratable acidity, density, sugar, and minerals concentrations was low.     

1-MCP结合冰温贮藏对葡萄采后品质及相关生理代谢的调控

以“乍娜”葡萄为试材,研究0.5μL/L和1.5μL/L 2个用量的1-MCP处理结合冰温贮藏(温度－0.3℃±0.3℃)对葡萄采后主要品质及相关生理指标的作用效果。结果表明：冰温贮藏结合2个浓度的1-MCP处理均可在不同程度上提高葡萄贮藏好果率并降低质量损失率和果梗褐变指数,抑制葡萄果穗呼吸强度和乙烯生成速率的增加,并能够有效抑制果实丙二醛(malondialdehyde,MDA)、超氧阴离子自由基(O2－ ·)、过氧化氢(H2O2)含量和脂氧合酶(lipoxygenase,LOX)活性的增加,保持或增大超氧化物歧化酶(superoxide dismutase,SOD)和过氧化物酶(peroxidase,POD)的活性;1μL/L 1-MCP处理结合冰温贮藏作用效果较好,使葡萄贮期较普通冷库对照延长20d。综上所述,适宜浓度的1-MCP处理结合冰温贮藏有利于提高葡萄采后贮藏品质和果实抗性、延缓果实衰老,在鲜食葡萄无硫保鲜方面具有非常好的应用前景。     

Effect of 1-methylcyclopropene and/or chitosan coating treatments on storage life and quality maintenance of Indian jujube fruit

Indian jujube (Ziziphphus mauritina, cv. ‘Cuimi’) fruits were harvested at stage of mature-green and then treated with 1-methylcyclopropene (1-MCP) at two doses (0 and 600 nl l⁻¹) for 12 h at room temperature. Half of the fruits were coated with 1.5 g/100 ml of chitosan (CTS) solution after 1-MCP treatment and subsequently stored at room temperature and 80-90% relative humidity (RH). Results indicated that 600 nl l⁻¹ of 1-MCP, 1.5 g/100 ml of CTS or their combination were effective in terms of senescence inhibition during storage and compared to control, the storage life was extended by 7, 5 and 8 d, respectively. Fruits treated with the combination of 1-MCP and CTS coating showed better retention of chlorophyll content, total soluble solids, ascorbic acid and fruit firmness, delayed climacteric ethylene evolution and respiration rate, reduced stem-end rots incidence, decreased PG and LOX activities than those with other treatments. Coating alone reduced weight loss and stem-end rots incidence. It delayed the declining firmness and the onset of climacteric ethylene production and respiration rate, but did not influence the peak levels of ethylene and respiration rates. The treatment with only 1-MCP delayed the degreening process and suppressed PG and LOX activities through 10 d at room temperature. The results showed that the treatment with the combination of 1-MCP and CTS coating improved greatly the storage life extension and quality maintenance of Indian jujube fruit at room temperature storage.     

Storage stability of a stimulant coconut water–acerola fruit juice beverage

The objective of this work was to study the stability of a beverage formulated with acerola fruit juice and green coconut water with added caffeine. The beverage was prepared with 25% acerola pulp, 75% green coconut water and sugar up to 12°Brix, and caffeine (125 mg L⁻¹), heat processed at 90 °C for 30 s and packed in 250-mL glass bottles. Chemical, physicochemical, microbiological and sensory analyses of the beverage were performed just after processing and during 6 months of storage at room temperature (27 °C). The vitamin C content decreased significantly throughout storage, from 399.5 to 189.6 mg 100 mL⁻¹, although it has remained relatively high. The anthocyanins initially present (0.025 mg 100 mL⁻¹) were completely lost during the storage at a mean rate of 4 μg 100 mL⁻¹ month⁻¹. The product was microbiologically stable during storage. Colour changes were also observed with absorbance at 420 nm, with average values ranging from 0.19 to 0.24. However, according to the sensory analyses the product was acceptable during the 6 months of storage, presenting sensory scores (colour, taste and global acceptance) from 6.5 to 5.5, which suggests its potential for market.