Postharvest physiology
Pooran Karimi Tazeiji; Somayeh Rastegar; Hamed Hasanzadeh Khankahdani
Abstract
Introduction
Date fruit (Phoenix dactylifera L.) is one of the oldest known fruit crops and is considered as an important component of the diet in many Middle Eastern and North African countries. The fruit of date is nutritious, which is incredibly rich in carbohydrates, minerals, dietary fibers and ...
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Introduction
Date fruit (Phoenix dactylifera L.) is one of the oldest known fruit crops and is considered as an important component of the diet in many Middle Eastern and North African countries. The fruit of date is nutritious, which is incredibly rich in carbohydrates, minerals, dietary fibers and amino acids. Dates are one of the most important tropical fruits that play an important role in the country's economy. Among the date palm cultivars in Hormozgan province, Piyarom is one of the most commercial cultivars.
Recent studies by scientists have shown that the use of chemical compounds, in addition to environmental hazards, will cause various diseases in consumers due to the residual transfer of toxins to their bodies. Therefore, the management orientation of food preservation methods has moved towards reducing and eliminating chemicals and determining suitable alternatives, so that a certain time frame was set for the removal of some of the most important tobacco toxins.
In recent years, attention has been paid to aloe vera gel as a coating layer for fruits and vegetables to maintain their storage quality, and because it has no smell or taste, eating it does not pose a problem for humans and it is even good for health. L-arginine is one of the 20 major amino acids of living cells, which is a semi-essential amino acid in the human body. L-arginine and D-arginine are natural forms of common isomers of this type of amino acid.
The aim of the present investigation was the assess the effect of L-Arginine and Aloe vera gel edible coating on maintaining the external properties and the quality of semi-dried date fruit cultivars including Piyarom during storage.
Material and Method
The experiment was conducted as a factorial arrangement in a completely randomized design. The first factor was including seven treatments consisting of control, L-Arginine (1, 2, and 8 mM) and Aloe vera gel (25, 50, and 75%) and the second factor included storing (sampling) time for 9 months. In every measurement, the different attributes were evaluated such as weight loss percent; TSS; total acid; total phenol; flavonoid; color indexes including L*, a*, and b*; and antioxidant capacity. The level of antioxidant activity was evaluated by antioxidant agents by the method described by based on the trapping of free radicals of 2, 2-diphenyl 1-picryl hydrazyl (DPPH). DPPH solution was well combined with the methanol extract by means of a vortex and was incubated in the dark for 30 min. Then the absorption rate was read at 517 nm using a spectrophotometer. The color was determined using a colorimeter (Minolta, CR-400, Japan) after different months of storage. All measurements were done in triplicates. L* (100=white, 0=black), a* (–green, +red) and b* (–blue, +yellow) values were obtained at 400-700 nm range. The assay of the total phenol content was performed by applying the Folin–Ciocalteu colorimetric procedure. The total soluble solid (TSS) content of the fruit juice obtained for each replicate was determined using a hand-held refractometer Atago (Atago Co. Japan) at 25 °C; the results are expressed as % (°Brix). Titratable acidity (TA) was measured by titrating diluted juice with 0.1 N NaOH to a phenolphthalein end-point (pH 8.1-8.3). The results are expressed as citric acid %.
Results and Discussion
Based on the results, the treatments of Aloe vera gel and L-Arginine had significant effect on the quantitative and qualitative traits of Piyarom date fruits during storage. Storing time had significant influence (p<0.01) on the all parameters so that by passing storage time, the parameters including L*, a*, b*, a weight loss percent significantly increased and the parameters such as phenol, flavonoid and antioxidant significantly decreased. In the Piyarom cultivar, the treatments had significant effects on a*, b*, weight loss percent, phenol, flavonoid, and antioxidant, but it had no significant influence on TSS and total acid, so that the highest a* and b* color indexes was observed in the use of L-Arginine 1 mM, the greatest phenol and flavonoid in the application of L-Arginine 2 mM, the lowest weight loss percent in the use of Aloe vera gel 25 and 75%, respectively.
Conclusion
According to the results, 1 mM L-arginine treatment and 75% Aloe vera gel had a more effective role in maintaining the storage quality of Piyarom dates. The use of these treatments requires more extensive research on soft and dry dates.
Postharvest physiology
Moazameh Shahabi; Somayeh Rastegar
Abstract
Introduction Narcissus (Narcissus tazetta) has high demand in flora markets due to its beauty, having a multi-floret flowerhead and delicate fragrance. The appearance quality and vase life of cut flowers decreased after harvest due to flower senescence, loss of petals turgor, reduced water absorption, ...
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Introduction Narcissus (Narcissus tazetta) has high demand in flora markets due to its beauty, having a multi-floret flowerhead and delicate fragrance. The appearance quality and vase life of cut flowers decreased after harvest due to flower senescence, loss of petals turgor, reduced water absorption, transpiration, fresh weight loss, and reduced water potential which reduces the economic and ornamental value of flowers at the consumer. One of the important reasons for the poor postharvest quality of Narcissus tazetta is the loss of turgor and their high sensitivity to browning of the petals. Browning mechanisms are chemically divided into enzymatic and non-enzymatic browning reactions. Enzymatic browning, which causes important reactions and discoloration, is one of the important factors affecting the quality and shelf life of fresh produce. Previous studies have shown that the activity of polyphenol oxidase (PPO) and peroxidase (POD) is positively correlated with browning during the postharvest storage of fruits and vegetables. Nitric oxide (NO) is recognized as a biological messenger in plants. It is a highly reactive gaseous free radical. Optimum NO levels could delay the climacteric phase of many tropical fruits and prolong the post-harvest shelf life of a wide range of horticultural crops by preventing ripening and senescence. Nitric oxide also could prevent the activity of PPO, phenylalanine ammonialyase (PAL) and POD, and keep the highest activity of superoxide dismutase (SOD).Materials and MethodsNarcissus (Narcissus tazetta L. cv. Shahla e-Shiraz) cut flowers at their commercial maturity stage (Goose-neck) were harvested from a production field in Farse province and. then they were transported to the laboratory. Healthy and uniform cut flowers with the same number of buds, a similar size and growth status were selected. Cut flowers were subjected to pulsed treatment of sodium nitroprusside for 24 hours on two levels (25 and 50 μM) and then kept in containers. Samples were stored at 20 ± 2 °C, relative humidity of 70-60%, with light cycle of 12 hours light and 12 hours dark. In this experiment, various physiological and biochemical indices including apparent quality (wilting index), cell membrane stability index (%), petal relative water content (%), color index and browning using a colorimeter, relative weight using digital scale (g), flower diameter, PPO and POD were examined. Results and DiscussionSodium nitroprusside treatment reduced the browning process by reducing the activity of POD and PPO enzymes. The effect of sodium nitroprusside was concentration-dependent. Sodium nitroprusside maintains membrane stability by protecting the membrane and preventing lipoxygenase activity and scavenging free radicals that have attacked the membrane. Sodium nitroprusside-maintained flower diameter due to its role in eliminating free radicals, delaying the aging process and maintaining flower quality. Discoloration and browning reactions of cut flowers reduce their appearance quality, leading to economic loss. The browning of the petals due to senescence is one of the important factors limiting the vase life of narcissus. It has been shown that PPO and POD are the key enzymes for the oxidation of the phenolic substrate (especially simple phenols) and the production of the brown compounds. It has also been suggested that the stability index of the cell membrane, which represents the ion leakage of the tissues, is diminished extremely as the longevity is increased. Another effective factor in determining the quality and vase life of cut flowers is the water-holding ability and water balance of the cut flowers petals. Changes in the cut flower fresh weight could also be regarded as one of the most important postharvest physiological disorders that affected the quality, vase life and commercial value of the cut flowers. Fresh weight loss, which is one of the most important reasons for the wilting of the flowers, is due to the less water uptake and more respiration rate.Conclusion Sodium nitroprusside treatment maintained the quality of Narcissus tazetta L. cv. Shahla e-Shiraz by increasing the relative water content of the petals and maintaining the cell stability index, as well as reducing the activity of browning enzymes (PPO and POD).Of course, the concentration used was very important.The best results were observed at lower concentrations (25 μM) of sodium nitroprusside.
Fateme Shabbepour Bandari; Somayeh Rastegar; Mostafa Ghasemi
Abstract
Introduction: Ziziphus mauritiana is a drought-tolerant fruit tree that originated in Central Asia. Ziziphus mauritiana v. khormaee is one of the cultivars of Hindi Ber which was favored by many people in the world and Iran. Maintenance of fruit quality is critical while employing any new technology ...
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Introduction: Ziziphus mauritiana is a drought-tolerant fruit tree that originated in Central Asia. Ziziphus mauritiana v. khormaee is one of the cultivars of Hindi Ber which was favored by many people in the world and Iran. Maintenance of fruit quality is critical while employing any new technology for increasing production. Fruit quality such as color, firmness, size, antioxidant and pulp to seed ratio had important role in marketability of fruits that can be affected by some chemicals. The quality of fruit can be influenced by growth conditions, developmental stage at harvest and postharvest factors. Calcium treatment, either by prearrest foliar sprays or by postharvest dips, represents a safe and potentially effective method for increasing the quality of some fruits. Prearrest treatments are more effective when calcium is applied directly to the fruit surface, since calcium moves in the transpiration stream and little or no subsequent translocation occurs from leaf to fruit. Calcium is an essential element which involved in cell division, elongation and fruit growth. Polyamines have the properties of growth promoters. Exogenous application of PAs has been reported to improve fruit retention and yield of fruits. Although a number of studies demonstrated the significance of PAs in reducing fruit drop and improving yield in various fruit crops, information on their effects on fruit quality is scant. Salicylic acid (SA) is an endogenous growth regulator of phenolic nature, which participates in the regulation of physiological processes in plants. Little information is available on the effects of foliar application of different Pas, salicylic acid and calcium on the quality of Ber fruit.
Materials and Methods: In this study, we evaluated the effect of foliar application of calcium chloride, putrescine and salicylic acid in various concentrations on fruit quality and quantity characters of Hindi ber(Ziziphusmauritiana. khormaee). Fruits selected from trees of the same age with branches of the same height and spraying with calcium chloride (0.5 and 1.5%), putrescine (1 and 2 mM), salicylic acid (1 and 2 mM) and distilled water (control) in two stages before commercial maturity. First stage, when fruit were 5-10 mm in size and second stage, when fruit color break. After the harvest fruit were transferred immediately to the laboratory and measured quantitative and qualitative parameters such as firmness, fruit length, fruit diameter, volume of fruit juice, pulp to seed ratio, soluble solids, titratable acidity, pH, ascorbic acid, chlorophyll a, b and carotenoids, color parameters and antioxidant activity. The length and diameter of the fruit were measured using a micrometer caliper. Total soluble solids (TSS) were determined using a digital refractometer. Firmness values of each individual fruit were measured at two points of the equatorial region by using a texture analyzer with a 5 mm Lurton 5005 probe. Fruits surface color was measured on individual fruit from each replicate at two opposite sides using a chromameter (CR 400, Minolta).For vitamin C (ascorbic acid) determination the titrimetric method with 2, 6-dichlorophenolindophenol reagent was applied. Antioxidant activity of fruit was tested by free radical DPPH scavenging.
Results and Discussion: The results showed that foliar application of calcium chloride, putrescine and salicylic acid favorably was effective on quantitative and qualitativecharacteristics Hindi Ber genotype.Kormaed. In treated fruits, total soluble solids (TSS), carotenoids and a* value were less and degree of firmness, fruit length, diameter, volume of fruit juice, pulp to seed ratio, titratable acidity, ascorbic acid (vitamin C), antioxidant activity, chlorophyll a and b, chroma index and hue angle were higher than control. Parameters of L* and b* in treated fruits had not significant different with control. Control fruits had the minimum carotenoid and the maximum chlorophyll. Fruit treated with putrescin(2mM) and control has the highest L* value. Different concentration of treatment that used hadn’t any significant difference with together in antioxidant characters. Maximum and the minimum firmness were found in salicylic acid (1mM) and control respectively. Among different treatments, CaCl2 1.5% showed highest volume of fruit juice of course had not significant difference with other treatments. The highest total soluble solids observed in control and highest vitamin C value showed in putrescin treatments
Conclusions: Generally, our result showed treatments that study in this study were effective on quality of Ber fruit. Calcium chloride (0.5 %), putrescine (2 mM), salicylic acid (2 mM) had the best effect on fruit quality. Therefor this chemical can be used to improve Ber fruit quality for consumer and marketing.
Materials and Methods: In this study, we evaluated the effect of foliar application of calcium chloride, putrescine and salicylic acid in various concentrations on fruit quality and quantity charachters of Hindi ber (Ziziphus mauritiana genotype.khormaee). Fruits selected from trees of the same age with branches of the same height and spraying with calcium chloride (0/5 and 1.5%), putrescine (1 and 2 mM), salicylic acid (1 and 2 mM) and distilled water (control) in two stages before commercial maturity. First stage, when fruit were 5-10 mm in size and second stage, when fruit color break. After the harvest fruit were transferred immediately to the laboratory and measured quantitative and qualitative parameters such as firmness, fruit length, fruit diameter, volume of fruit juice, pulp to seed ratio, soluble solids, titratable acidity, pH, ascorbic acid, chlorophyll a, b and carotenoids, color parameters and antioxidant activity. The length and diameter of the fruit were measured using a micrometer caliper. Total soluble solids (TSS) were determined using a digital refractometer. Firmness values of each individual fruit were measured at two points of the equatorial region by using a texture analyzer with a 5 mm Lurton 5005 probe. Fruits surface color was measured on individual fruit from each replicate at two opposite sides using a chromameter (CR 400, Minolta). For vitamin C (ascorbic acid) determination the titrimetric method with 2, 6-dichlorophenolindophenol reagent was applied. Free radical scavenging activity (antioxidant activity) of fruit was tested by DPPH.
Results and Discussion: The results showed that foliar application of calcium chloride, putrescine and salicylic acid favorably was effective on quantitative and qualitative characteristics Hindi ber genotype. Kormaed. In Treated Fruits, Total Soluble Solids (TSS), carotenoids and a* value were less and degree of firmness, fruit length, diameter, volume of fruit juice, pulp to seed ratio, titratable acidity, Ascorbic acid (vitamin C), antioxidant activity, chlorophyll a and b, chroma index and hue angle were higher than control. Parameters of L* and b* in treated fruits had not significant different with control. Control fruits had the minimum carotenoid and the maximum chlorophyll rather than other treatments. Fruit treated with Putrescin (2mM) and control has the highest L* value. Different concentration of treatment that used hadn’t any significant difference with together in antioxidant characters. Maximum and the minimum firmness were found in Salicylic acid (1Mm) and control respectively. Among different treatments, Cacl2 1.5% showed highest volume of fruit juice of course had not significant difference with other treatments. Control showed the highest Total Soluble Solids and significant differences with other fruits. Putrescin in both concentration had highest vitamin C content that had significant difference with control fruits.
Conclusions: Generally, our result showed treatment that study in this study were effect on quality of Ber fruit. Calcium chloride (0/5 %), putrescine (2 mM), salicylic acid (2 mM) had the best effect on fruit quality. Therefor this chemical can be used for improve Ber fruit quality for consumer and marketing.
Somayeh Rastegar; Majid Rahemi
Abstract
In this research different compounds such as moisture,protein,nutrition,fructose and glucose,cartenoid,organic acid,phenolic acid of piarom,shahani and deiry were studied.Suger was analyzed by (HPAEC-PAD). organic acids and phenoilc acids were studied by (HPLC). According to our result, shahani, piarom ...
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In this research different compounds such as moisture,protein,nutrition,fructose and glucose,cartenoid,organic acid,phenolic acid of piarom,shahani and deiry were studied.Suger was analyzed by (HPAEC-PAD). organic acids and phenoilc acids were studied by (HPLC). According to our result, shahani, piarom and deiry as soft, semi-dry and dry cultivars showed significant differences (p < 0.05) between most properties. Piarom has the highest organic acid compared other cultivar. Piarom has the highest organic acid, but in nutrition, total phenol and phenolic acids, deiry has first value. In three cultivars, among the minerals studied, potassium was most abundant with a concentration of 1170–2440 mg/100 g. Shahani has the highest reducing sugar (68.8%) and showed significant differences in compared to piarom and deiry. Deiry has the highest proteins (7.3%) as compared to other cultivars
