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Best heat treatment and storage temperature for dates harvested at the Tamar stage
In the world the date palm cultivated on an area of 1 353 159 hectares with nearly 100 million palm trees and a production of 8 460 443 tons [1] (*). The date palm cultivation in Algeria occupies an area of 167,269 hectares with 18.5 million palm trees and a production of nearly 1 million and 29,596 tones [2]. Dates are a main income source and staple food for local populations in many countries in which they are cultivated, and have played significant roles in the economy, society, and environment of those countries [3]. The largest consumption of dates is at Tamar stage due to their good storability and availability all year around [4]. Typically, date-flesh at its Tamar stage contains water (7-38 g/100 g), total sugars (44-88 g/100 g), fat (0.1-3.3 g/100 g), protein (1.5-5.4 g/100 g), dietary fiber (6.4-11.5 g/100 g), minerals, vitamins (such as vitamin C, B1, B2, B5,
25 August, 2023
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?B9,?B12, A, riboflavin, and niacin), and phenolic compounds [4]. The physical and compositional characteristic of date fruit is of prime importance for its quality, and varied?strongly depending on the variety, maturity, processing and?storage conditions [5]. The nutritional, physicochemical,?mechanical, structural, textural, and sensory properties are?necessary for determining it?s processing, storage stability,?and consumer acceptability [6]. Research on date fruit has shown that the fruit has a wide?range of uses and applications [7]. Although several works?have been carried out on date fruit, research studies?concerned with the nutritional and physico-chemical?characteristics of the fruit are very limited [7]. Shape,?morphological dimensions, volume, and surface area are?important characteristics for handling, processing and?storage of agricultural products. The morphological?characteristics of dates vary with the varieties, maturity,?and processing conditions. The length, width, and mass of?dates vary from 3.1-6.0 cm, 1.6-2.3 cm and 4.3-12.0 g,?respectively [4]. Thermal treatmentGiven that the dates, at harvest, cover a wide range in?humidity (from 10% to 45% on average), the heat?treatments intended for them, including mainly hydration?and drying, are carried out with the aim of improve the?quality of the fruit by homogenizing it with respect to its?humidity and by extending its shelf life during storage and?marketing [8]. The heat treatment (at 55?C/20min) of dates?has shown a remarkable effect in limiting the infestation of?Deglet Nour date stocks, even not heat treated, both at?room temperature and at 10?C [9]. Heat treatments are?more and more accepted as replacement treatments for?methyl bromide; however, determining the most sensitive?stages of biological development is essential to the?development of disinfection protocols based on thermal?energy [9]. To determine the most thermally resistant life?stage, Wang et al., and Khali, [10, 11] selected nine?combinations 48 ?C for 2 min, 48 ?C for 5 min, 48 ?C for?10 min, 50 ?C for 2 min, 50 ?C for 3 min, 50?C for 5 min,?52?C for 05 min, 52?C for 1 min and 52?C for 2 min.These authors showed that all larval forms and eggs were?destroyed by treatments of 50?C for 5 min and 52?C/2 min.The objective of this experimental research is to see the?influence of heat treatment at the 55?C/20min thermal scale?[11], chosen as a postharvest disinfection technique, on the?morphological characteristics of Deglet Nour date (Phoenix?dactylifera L.) during storage. ConclusionThe findings of this study indicated that harvesting?Deglet Nour dates at the Tamar stage followed by a heat?treatment (at 55 ?2?C) of the fruits, storing of 5 months at?22 ?1?C with 75 to 80% RH and 10 ?1?C with 85 to 90%?RH is a promising method for maintaining date palm fruit?storage quality. There is a significant different between the?treatments on the quality of date palm fruits. The?interaction of heat treatment and storage temperature at 10 ?1?C affected the width of the treated Deglet Nour?date fruits significantly (p<0.05). Finally, the combination?between the heat treatment (at 55 ?2?C) and the storage?temperature at 22 ?1?C was the best treatment to maintain?and improve the date palm quality. AbstractThe effect of heat treatment on the quality of date?s fruits (Phoenix dactylifera L.) was studied?for five months of storage at room temperature 22 ?1?C with 75 to 80% RH, and 10 ?1?C with?85 to 90% RH. The results indicated that during storage, the morphological characteristics?changed significantly. The major change was observed for the sample of heat treated dates?stored at 10 ?1?C has the highest weight compared to the other samples of the dates studied.The R-Index quality showed a rate of 8.56% and which increased in heat treated dates to reach?8.87%. The width of date samples stored at 10?C is large compared to heat treated and nonheat treated samples stored at room temperature. Harvesting at the Tamar stage followed by?heat treatment of the fruits has proven to be a promising method to maintain the storage?quality of date palm fruits.(*) References in the original paper, below SourcesMorphological properties of heat treated date fruits (Phoenix dactylifera?L.) in postharvestMarouf Aribi Mohameda and Khali MustaphacAlgerian Journal of Engineering and Technology 07 (2022) 055?062Journal homepage: https://jetjournal.org/index.php/ajethttps://scholar.google.es/scholar_url?url=https://www.jetjournal.org/index.php/ajet/article/download/183/86&hl=es&sa=X&d=11236221616304236337&ei=exdzY-rWNpD-yQS3_I_wDA&scisig=AAGBfm2Dz5-MCJrNoD73Ls2sJ43YX1XKGA&oi=scholaralrt&hist=raTGsR8AAAAJ:3540667690812997231:AAGBfm3wBiAJ5GXH1-P9cqyPOPxl36BAfQ&html=&pos=5&folt=kw-top Picure, Deglet Noor Dates, https://oasisdate.com/pages/deglet-noor-dates
