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Volume 5 Number 1 2011
CONTENTS AND ABSTRACTS
María Victoria Agüero, Alejandra Ponce, Alicia Bevilacqua, Sara Inés Roura (Argentina) Postharvest Quality Losses of Butter Lettuce as Affected by Leaf Age and Temperature (pp 1-6)
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Original Research Paper: Whole lettuce plants were used to evaluate the effect of leaf age on ascorbic acid (AA), chlorophyll (C), microbial quality (M), colour and overall visual quality of fresh butter lettuce exposed at three isothermal environmental conditions: 0-2, 10-12 and 20-22°C during first 24 hours after harvest in order to describe quality changes in the product during transport from the field to the distribution center. Relative humidity was the optimal (97-99%). Temperature, leaf age and time significantly affected the quality parameters under study. Even though lettuces were stored under optimal temperature (0-2°C), significant C decreases were observed in outer leaves, increasing the loss at higher temperatures. The highest losses took place in the first 6 h, and then the rate of loss was significantly lower. Although the inner leaves presented changes in redness/greenness colour parameter, no significant changes in C were detected in these leaves. Increments in microbial counts occurred, and resulted higher in outer leaves respect to mid or inner ones. Increments were greater at higher temperature. Ascorbic acid significantly decreased at the three temperatures. After 6 h of storage, the AA losses were of 50% at 10-12 or 20-22°C, and of 30% at 0-2°C.
Kablan Tano (Canada/Côte d’Ivoire), Emma F. Assemand, Rose Koffi-Nevry (Côte d’Ivoire), Robert W. Lencki, Joseph Arul (Canada) Physiological Characteristics of Mushrooms, Strawberries, Broccoli and Tomatoes: Respiration in Air and Modified Atmosphere and Transpiration (pp 7-14)
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Original Research Paper: Respiration and transpiration of mushrooms (Agaricus Bisporus cv. ‘U3 Sylvan 381’), strawberries (Fragaria x ananassa Duch, cv. ‘Kent’), broccoli (Brassica oleracea L. cv. ‘Acadi’) and tomatoes (Lycopersicon esculentum Mill. cv. ‘Trust’) were determined under different temperatures, atmospheric and humidity conditions in order to get information for modified humidity atmosphere packaging design. The respiration rates of all products under optimum modified atmospheres were 40 to 60% lower than in air. The respiration quotients (RQ) for the products studied were always lower than 1.0, but were significantly (p<0.05) higher under optimal modified atmosphere conditions than in air. The Q10 values for respiration varied from 2.1 (for tomatoes) to 3.3 (for mushroom). The transpiration rate was the sum of inherent, heat-transfer-induced and mass-transfer-induced transpiration. At low relative humidity, mass-transfer-induced transpiration was the dominant mechanism for all fruit and vegetables. This study provides a better understanding of the interrelationship between respiration and transpiration of fruit and vegetables under different temperatures, atmospheres and relative humidities conditions, which will lead to improve the design of controlled and modified atmosphere and humidity packaging.
Benjamin N. Yao, Kablan Tano, Emma F. Assemand, Rose Koffi-Nevry, Gérard K. Bédié, Georges Amani (Côte d’Ivoire) Effect of the Maturity Stage and Storage Temperature on the Postharvest Quality of Carica papaya L. Variety Solo 8 (pp 15-21)
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Original Research Paper: The level of maturity of Carica papaya L. cv. ‘Solo 8’ at harvest influences considerably most of its flavoring characteristics during ripening. The objective of this study was to determine the level of maturity at harvesting that provides the optimum organoleptic characteristics of C. papaya and to find the best temperature for its storage. Three maturity stages were selected (green immature: fruit had green skin without yellow spots, green mature: fruit presented 1/32nd of the yellow skin and advanced maturity: fruit presented 1/8th of the yellow skin). Thirty six fruit at each maturity stage were stored at 15, 22, and 28°C for 12 days and infection rate, weight lost, acidity, pH, firmness, vitamin C content, reducing and total sugars contents, and index of refraction were measured every four days. In addition, trained panelists performed a sensory evaluation of the fruit. At the mature and advanced stages, the fruits had a sweet taste with total sugar content varying from 3.42 to 6.43 g/100 g at day 0 to 7.2 to 8.39 g/100 g at day 12, respectively. Furthermore, the infection rate and the loss of weight of the fruit were higher at the advanced and green immature stages. The content of vitamin C was higher in fruit stored at 15°C compared to those stored at 22 and 28°C. This study indicates that C. papaya stored at 15°C for 12 days at the green mature stage presented the best organoleptic characteristics.
Bal Vipan Chandar Mahajan, Kulbir Singh Brar, Birinder Singh Ghuman, Rajbir Singh Boora (India) Effect of Pre-Storage Treatments of Calcium Chloride and Gibberellic Acid on Storage Behaviour and Quality of Guava Fruits (pp 22-25)
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Original Research Paper: Guava fruits of cultivar ‘Allahabad Safeda’ were harvested at the green mature stage. The fruits were given postharvest treatments of calcium chloride (CaCl2: 1, 2, 3%), gibberelic acid (GA3: 25, 50, 75 ppm) each for 5 min. The fruits were air dried and packed in corrugated fibre board boxes and stored in a walk-in cold-room maintained at 6 ± 1°C and 90-95% relative humidity. A control lot of fruit (without any treatment) was also stored under same conditions. The fruits were analysed for various quality attributes at different storage intervals until 4 weeks. The postharvest application of CaCl2 (2%) extended the storage life of guava fruits up to 4 weeks with minimum weight loss, desirable firmness and highly acceptable quality.
Lixia Hou, Hui Hao, Xiyan Yu (China) Application of CPPU on Muskmelon Alters Fruit Size and Quality (pp 26-29)
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Original Research Paper: The cytokinin-active compound, N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), applied on unpollinated and pollinated ovaries, affected the fruit growth and quality of muskmelon. 10, 20 and 30 mg L-1 CPPU applications on the emasculated ovary on day 1 (0 day after anthesis) effectively induced fruit parthenocarpy. However, fruit growth was slightly reduced and the weights of the mature fruits were approximately 93-96% of the control fruit (seeded fruit set by hand pollination). Moreover, the contents of sugar, vitamin C and the esters volatiles in fruit were significantly lower than those of the control fruit. These results indicate that the seeds play important roles in determining fruit growth and quality of muskmelon. On the other hand, CPPU application on the pollinated fruit markedly enhanced fruit growth and improved fruit quality. Among the assayed treatments, 20 mg L-1 CPPU was effective for enhancing fruit growth and quality. Interestingly, we also found that CPPU applications on the pollinated fruit enhanced significantly the length and diameter of the mature fruits. Moreover, the increase in the length of the mature fruits was especially significant, resulting in elongated fruit shape of the treated fruits. Results indicate that the appropriate concentration of CPPU, when applied to pollinated fruit, is an effective technique to increase the fruit growth and quality of muskmelon.
George Sodah Ayernor, Emmanuel Ohene Afoakwa, Paa Kow Bartels, Agnes Simpson Budu (Ghana) Application of Response Surface Methodology for Studying the Effects of Gestation and Post-Harvest Storage on the Shrinkage Characteristics of Pineapple cv. ‘Smooth Cayenne’ Fruits (pp 30-33)
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Original Research Paper: Response surface methodology was used to study the combined effect of gestation period and storage time on the shrinkage characteristics of pineapples fruits during post-harvest storage. A 6 × 10 factorial experimental design was used to study the combined effect of gestation period (140, 144, 148, 152, 156 and 160 days after floral induction) and storage time (0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days) on the shrinkage evolution, shell colour break and crown withering index. Regression models were developed to predict the variables and their effects on the studied indices. Gestation period and storage time showed varied influences in dictating the shrinkage characteristics of pineapple fruits. Increasing storage time caused consistent and significant increases in the levels of shrinkage evolution, shell colour break and crown withering index during the 10-day storage period. Shrinkage evolution and shell colour break were not influenced by the gestation period (days of harvest after floral induction [FI]) irrespective of storage time. On the contrary, crown withering index was influenced by gestation period. Fruits harvested after 160 days at FI had higher mean crown withering index than those harvested after 140 days after FI, with the actual withering showing after 5 days of storage, suggesting that withering of pineapple cv. ‘Smooth cayenne’ fruits is influenced by both gestation period and storage time. Thus, response surface methodology could be employed to study the mass shrinkage characteristics of pineapple fruits as influenced by gestation period at FI and post-harvest storage time.
George Sodah Ayernor, Emmanuel Ohene Afoakwa, Paa Kow Bartels, Agnes Simpson Budu (Ghana) Effect of Polymeric Coating on the Post-Harvest Quality Characteristics of Pineapple cv. ‘Smooth Cayenne’ Fruits (pp 34-38)
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Original Research Paper: Investigations were conducted to determine the effect of polymeric coating on the post-harvest quality characteristics of pineapple (Ananas comosus) cv. ‘Smooth Cayenne’ fruits. A 4 × 2 × 4 factorial experimental design with polymeric coating concentration (0, 5, 7.5 and 10%), storage temperature (8 and 28°C) and storage period (0, 4, 7 and 10 days) was performed. Vitamin C, total sugars, titratable acidity, astringency index, pH, translucency and fruit texture were determined using standard analytical methods. Storage significantly (P ≤ 0.05) decreased vitamin C and total sugar content with a concomitant increase in acidity, astringency, translucency and fruit texture. Low temperature storage however minimized the effect of the observed differences. Polymeric coating influenced the physical and chemical qualities of the fruits with 5 and 7.5% polymeric coatings being the most effective preservative levels. Polymeric coating can therefore be applied to pineapple cv. ‘Smooth cayenne’ fruits prior to storage to effectively prolong the chemical and physical quality characteristics of the fruits.
Olufunke O. Ezekiel, Rasheed K. Mustapha, Taiwo O. Olurin (Nigeria) Effect of Salt on Colour Degradation Kinetics of Visual Green Colour in Fluted Pumpkin (Telfairia occidentalis) Leaves (pp 39-42)
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Original Research Paper: The effect of common salt (0, 1, and 2% by weight) on visual green colour degradation of fluted pumpkin (Telfairia occidentalis) puree over a temperature range of 50–100° C was studied. Hunter colour scale values L (lightness), a (greenness or redness)and b (blueness or yellowness) of each treated samples were measured. The visual colour was evaluated using a Hunter lab colorimeter in terms of L, a and b. The results were analysed using Oakdale Engineering Datafit 8.2. The degradation of visual green colour of fluted pumpkin increased with an increase in heat treatment time and salt concentration. The degradation as measured by -a value followed a first order kinetics. There was consistent decrease in L and -a values with an increase in treatment time and temperature. During heat processing, the puree turned olive green and the a value changed from an initial value of -11.32 to -10.40, -10.73 and -10.87 at 50°C for the 0, 1 and 2% level of salt addition, respectively. The corresponding values at 100°C were -3.11, -3.65 and -3.72, respectively. There is stabilization of green colour in thermally processed fluted pumpkin puree containing salt which decreases the rate of chlorophyll degradation. The stabilizing effect of salt is not well established and no information is available on fluted pumpkin leaves, especially in term of visual colour. The paper established the stabilizing effect of salt on fluted pumpkin leaves and modelled the degradation kinetics with Arrhenius equation.
Victor Rodov, Beatrice Nafussi, Shimshon Ben-Yehoshua (Israel) Essential Oil Components as Potential Means to Control Penicillium digitatum Pers. (Sacc.) and Other Postharvest Pathogens of Citrus Fruit (pp 43-50)
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Original Research Paper: The studies were conducted on 37 compounds present in citrus essential oils, to test their activity against Penicillium digitatum Pers. (Sacc.) by three in vitro assays: agar diffusion, amended growth medium (“poisoned food”) and vapor assay. The aliphatic alcohols 1-nonanol, 1-decanol and especially 1-octanol exhibited the highest activities against P. digitatum, as assayed by all the methods used. The terpenoid compounds perillalcohol, perillaldehyde, citral, terpineol, carveol and citronellol, as well as the aromatic compound cinnamaldehyde, which is not a component of citrus oil but was used as a reference material, exhibited high activity against P. digitatum. The hydrocarbons d-limonene and myrcene, and the esters octyl acetate, decyl acetate, geranyl acetate, neryl acetate and linalyl acetate did not inhibit this fungus. 1-Octanol, perillaldehyde, citral, perillalcohol and terpineol were fungicidal, whereas 1-decanol, 1-nonanol, carveol and citronellol were only fungistatic. 1-Octanol, 1-decanol, perillaldehyde and citral also showed antifungal activity against Alternaria citri Ell. et Pierce and Penicillium italicum Wehmer. In addition 1-octanol and perillaldehyde were active against Geotrichum candidum Link. The selected promising compounds 1-octanol and citral were further tested in vivo on P. digitatum-inoculated lemons as active ingredients of microbiocidal formulations. Application of formulations comprising 1-octanol and citral either separately or together inhibited decay of P. digitatum-inoculated lemons for three weeks after inoculation without visible phytotoxic damage or perceivable off-odor, although total control was not achieved. The results obtained demonstrated the potential of essential oil components as postharvest citrus fungicides.
Alfonso Vargas, Johnny A. Lopez (Costa Rica) Effect of Dose Rate, Application Method and Commercial Formulations of GA3 on Banana (Musa AAA) Fruit Green Life (pp 51-55)
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Original Research Paper: The postharvest effect of GA3 on banana (Musa AAA, Cavendish subgroup) fruit green life was evaluated throughout four experiments in the Caribbean side of Costa Rica. Experiment #1 evaluated GA3 dose rates of 0, 750, 1.500 and 2000 mg kg-1, experiments #2 and #3 dose rates of 0, 500, 750, 1000 and 1500 mg kg-1; and experiment #4 dose rates of 0, 500, 1000 and 1500 mg kg-1. Two application methods were implemented (brushing and spraying) using RyzUp® 40% WSG and were evaluated in experiments #1, 2 and 3, while two commercial formulations of GA3 (RyzUp® 40% WSG and RyzUp® 4 LS) applied by brush only was evaluated in experiment #4. GA3 was applied in combination with the fungicides and Alum used for crown rot protection. In all experiments, differences (P < 0.0437) were found between the untreated control and the remaining GA3 group dose rates (P < 0.0113). With the exception of spray application in experiment #3 where a possible effect was noted (P = 0.0506), there was no increasing linear effect (P > 0.2074) nor quadratic (P > 0.1923) effect of GA3 dose rate on fruit green life. No differences between application methods (P > 0.3066) nor between GA3 formulations (P = 0.8622) were observed. GA3 delayed maturation in comparison to the untreated control by 10.6, 9.5 and 12.4 days in experiments #1, #2 and #4, respectively; and 24.5 and 9.5 days, respectively for the brush and spray applications in experiment #3. There was no difference in banana fruit green life with either application methods (P > 0.3066) or either commercial formulations (P = 0.8622). Under packing house commercial process and storage conditions utilized in these studies it was possible to delay banana fruit ripening by the postharvest use of GA3.
Alfonso Vargas, Maricruz Ramírez-Sánchez, Marco V. Sáenz, Alvaro Segura, Fabio A. Blanco (Costa Rica) Effect of Natural Flooding and Postharvest Gibberellic Acid Application on Banana Fruits (pp 56-60)
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Original Research Paper: The effect of natural flooding for a period of 144 h was evaluated on banana fruit (Musa AAA, cv. ‘Grande Naine’) resulting from fruiting plants with physiological bunch age at the moment of the flood event of 10, 9, 8 and 7 weeks, from flooded (F) or non-flooded (NF) areas. Banana fruit of the F area were treated with GA3 (0, 400, 800, 1200, 1600 mg kg-1) as a postharvest treatment. The variables measured were green and yellow life, pulp firmness (kg), soluble solids content (SSC; °Brix) and total titratable acidity (TTA; % of malic acid). A comparison of these variables between F and NF control areas determined the flooding effect. The effect of GA3 evaluated only in the F area was determined by regression analysis. During the storage period of 21 days at 14°C (simulation transportation time) neither fruit from F nor NF areas showed any sign of natural ripening onset. The flooding event did not have any negative influence on the ripening process of the fruit. Flooding did not have any influence on firmness, SSC and TTA of harvested fruit. Independent of the GA3 dose, the results showed an increment in SSC (19.04 to 23.17%) and TTA (0.31 to 0.42%) with an increase in the age of the fruit at the time of the flooding event. In general, different GA3 rates applied to fruit from the F areas did not have an effect on the measured variables of yellow life, including the time to reach Grade 5 of maturity. These results suggest that the commercial practice of discarding bunches in the field after a flooding period may not be necessary in all cases.
Gérard Ngoh Newilah, Kodjo Tomekpe, Elie Fokou, François-Xavier Etoa (Cameroon) Effect of Ripening on Physicochemical Composition of Plantain Cultivars and Musa Hybrids Grown in Cameroon (pp 61-68)
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Original Research Paper: Fruits from 11 local plantain cultivars and four plantain hybrids were evaluated for some physicochemical changes during ripening. At harvest, peel thickness and fruit grade as well as fruit length varied considerably according to Musa type, but the local plantain cultivar Biya 2 exhibited the highest values (4.20 mm, 5.93 cm and 43.60 cm, respectively). During post harvest maturation of the fruits, pulp to peel ratio, total soluble extracts and total titratable acidity of the pulps increased significantly while firmness, pH and dry matter content of the pulps decreased considerably and sometimes significantly. All the parameters investigated varied significantly according to plantain cultivars and hybrids. Coupled with pulp colour, fruit grade and length as well as sensorial and nutritional qualities are important elements that enable processors to obtain high quality products and breeder’s decisions during the creation and selection of new plantain hybrids.
Hana Zandkarimi, Alireza Talaie, Reza Fatahi (Iran), Jaime A. Teixeira da Silva (Japan) Evaluation of Some Lime and Lemon Accessions by using Morphological Characterization in Hormozgan Province (Iran) (pp 69-76)
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Original Research Paper: In this study, some physical and chemical characteristics of lime and lemon fruits from 19 genotypes growing in Hormozgan province located in the south of Iran were investigated, including fruit length and diameter, seed number and percentage of fruit juice and peel. Some characters of fruit juice, namely pH, titration acidity, total soluble solids and antioxidant activity, were also determined. According to the results of bivariate simple correlation analysis, there were significant positive and negative correlations between some important characters. Factor analysis showed that the main factor was composed by fruit weight, fruit length and some characters of fruit juice and seed. The most effective characters were categorized into 7 main factors (with an Eigen value ≥ 1) that contributed to 85.98% of total variance. Cluster analysis was performed by using these 7 factors and genotypes were divided into 5 main clusters that included lime and lemon and unknown genotypes. Some lime genotypes were different in some characters such as fruit shape and size, and peel thickness. The lemon groups contained the cultivars ‘Eureka’, ‘Lisbon’ and ‘Meyer’. Another group contained one genotype that has large fruit similar to orange but is very acid, like a lemon. Some unknown acid citrus were different from either limes or lemons.
Cong Zhao, Leyuan Ma, Hui Hao, Xiyan Yu (China) Volatile Precursors and Aroma-Related Enzyme Activities during Fruit Maturation of Muskmelon (pp 77-79)
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Short Communication: Fatty acids and amino acids serve as ester precursors, in addition to lipoxyaenase (LOX; EC 1.13.11.12), alcohol dehydrogenase (ADH; EC 1.1.1.1) and alcohol o-acyltransferase (AAT; EC 2.3.1.84) activities, were assessed during maturation of climacteric and non-climacteric muskmelons. The results showed that the levels of the main fatty acids related to aroma formation containing oleic acid, linoleic acid and linolenic acid during fruit development of ‘Shannong Golden1’, a climacteric muskmelon were much higher than those in fruits of ‘Sweet Delight’, a non-climacteric muskmelon. The amino acids contents were very high in 15 days after pollination (DAP) fruit of ‘Shannong Golden1’, but dramatically decreased in 30 DAP fruit and reached the lowest levels in mature fruit. But, these amino acids levels almost had no changes during fruit development of ‘Sweet Delight’. In contrast to amino acids levels, ADH and LOX activities showed almost the same change trends, however, AAT activities were significantly different during fruit development of these two cultivars. Together, our data suggested that AAT activity, fatty acids and amino acids contents may play important roles and LOX and ADH may be not the limiting factors in ester volatiles production in muskmelon fruit.
Luke N. Ukiwe, Jude I. Alinnor (Nigeria) Extraction of Pectin from Pineapple (Ananas comosus) Peel using Inorganic/Organic Acids and Aluminum Chloride (pp 80-83)
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Research Note: The ability of inorganic acids (HCL, H2SO4, HNO3) and organic acids (citric, acetic, oxalic) to extract pectin from pineapple (Ananas comosus) cv. ‘Agege Parson Brown’ peel was investigated. Results obtained using ethanol precipitation showed that HNO3 was the best inorganic acid for pectin extraction (1.6/200 g sample), while acetic acid was also observed as the best organic acid for pectin extraction (0.6/200 g sample). However, AlCl3 extracted the highest amount of pectin overall (4.8/200 g). The degree of methoxylation ranged from 2.40 to 5.60% for the inorganic acids, while for the organic acids and AlCl3, the range was 2.80 to 3.89%. AlCl3 was the best substance for pectin extraction. |
