Agricultural Engineering Research Journal 5(1): 01-06, 015 ISSN 18-3906 IDOSI Publications, 015 DOI: 10.589/idosi.aerj.015.5.1.1130 Effect of Wrapping Materials and Cold Storage Durations on Quality of Plum (cv. Shablon) 1 1 Fariborz Naserzaeim, Majid Rashidi and Saeed Sayfzadeh 1 Department of Agricultural Machinery, Takestan Branch, Islamic Azad University, Takestan, Iran Department of Agronomy, Takestan Branch, Islamic Azad University, Takestan, Iran Abstract: This study was conducted on the effect of wrapping material and cold storage duration on plum (cv. Shablon) during cold storage at -1 C temperature and 98% relative humidity. Three wrapping materials (news paper + straw, kraft paper and kraft paper + straw) and five cold storage durations (0, 8, 16, 4 and 3-day) were investigated for some quality characteristics of plum including water content, total soluble solids (TSS) and firmness. The experiment was laid out in Factorial Completely Randomized Design (FCRD) with four replications for each one of factors. The data collected were subjected to Analysis of Variance (ANOVA) and Duncan s Multiple Range Test (DMRT) at 1% probability was performed to compare the means of different treatments. The statistical results of the study indicated that wrapping material and cold storage duration significantly (P 0.01) affected water content and firmness. Although wrapping material had no significant effect (P 0.01) on TSS, cold storage duration significantly (P 0.01) affected it. Results of the study also indicated that water content and firmness decreased by increasing cold storage duration, whereas TSS frequently decreased and increased by increasing cold storage duration. In addition, kraft paper for water content and kraft paper + straw for TSS and firmness were the best wrapping materials. Key words:plum Wrapping material Cold storage duration Water content Total soluble solids (TSS) Firmness INTRODUCTION Plums are produced around the world and China is the world s largest producer. The ten largest producers of A plum (Prunus domestica) is a drupe fruit of the plums are China, Romania, USA, Serbia, Chile, France, genus Prunus. The subgenus is distinguished from Iran, Turkey, Italy and India. Iran products nearly other subgenera (peaches, cherries, bird cherries, etc.) in th about 69,139 tons of plum and is ranked 7 in the world the shoots having a terminal bud and solitary side buds []. But, Iranian plums are not exported because of (not clustered), the flowers in groups of one to five variability in size and shape and lack of suitable together on short stems and the fruit having a groove packaging [3]. running down one side and a smooth stone (or pit). Methods that are being used to preserve whole The commercially important plum trees are medium sized, fruits and vegetables during storage and marketing are usually pruned to 5-6 meters height. The tree is of medium generally based on refrigeration with or without control hardiness. Fruits are usually of medium size, between 1 to of composition of the atmosphere [4, 5]. However, 3 inches in diameter, globose to oval. The flesh is firm, temperature, atmosphere, relative humidity and sanitation juicy and mealy. The fruit s peel is smooth, with a natural must be regulated to maintain quality of them [6, 7]. In this waxy surface that adheres to the flesh. The fruit has a direction, several methods that have been used are single large seed. Plum fruit tastes sweet and/or tart; the refrigeration, controlled atmosphere packaging, modified skin may be particularly tart. It is juicy and can be eaten atmosphere packaging and chemical preservatives [8-10]. fresh or used in jam-making or other recipes. Plums come The most prevalent method is rapid cooling at a low in a wide variety of colors and sizes. Some are much temperature with high relative humidity [11]. However, low firmer-fleshed than others and some have yellow, white, temperature storage is not economically feasible in most green or red flesh, with equally varying skin color [1]. developing countries [5, 1]. Corresponding Author: Majid Rashidi, Department of Agricultural Machinery, Takestan Branch, Islamic Azad University, Takestan, Iran. E-mail: majidrashidi81@yahoo.com - m.rashidi@tiau.ac.ir. 1
Agric. Engineering Res. J., 5(1): 01-06, 015 Fungicides control postharvest decay of whole fruits, Total Soluble Solids (TSS): The TSS of plums was but they leave residues that are potential risks to humans measured using an ATC-1E handheld refractometer and the environment [1]. In addition, many consumers (ATAGO, Japan) at 0 C temperature (Fig. 1). are suspicious of chemicals in their foods, especially in fruits and vegetables [9]. Sulfites were effective chemical Firmness: The firmness of plums was measured using a preservative as they were both inhibitors of enzymatic handheld fruit penetrometer or fruit firmness tester browning and antimicrobial. But their use has been (Fig. ). The penetrometer had a diameter of 8.0 mm and banned due to adverse reaction in consumers [9, 13]. the maximum pressure measured during each test based Moreover, chemical preservatives affect the flavor of - on kg cm was considered as stiffness. fruits and vegetables [14]. Coatings, films and wrapping materials are also Statistical Analysis: The experiment was laid out in effective in reducing desiccation (moisture loss), but are Factorial Completely Randomized Design (FCRD) with subject to microbial growth and disposal problems three wrapping materials (news paper + straw, kraft paper [10, 15]. Many years of research are conducted to develop and kraft paper + straw) and five cold storage durations a material that would cover fruit so that an internal (0, 8, 16, 4 and 3-day) at -1 C temperature and 98% modified atmosphere would develop [16, 17]. relative humidity with four replications for each one of In this paper, the effect of wrapping material and factors. The effect of the factors on each quality cold storage duration on some quality characteristics of characteristic was determined by analysis of variance plum (cv. Shablon) including water content, total soluble (ANOVA) using SPSS 1.0 (Version, 003). Also, solids (TSS) and firmness during cold storage at -1 C Duncan s Multiple Range Test (DMRT) at 1% probability temperature and 98% relative humidity is reported. was performed to compare the means of different treatments. MATERIALS AND METHODS RESULTS AND DISCUSSION Plant Materials: Plums (cv. Shablon) were purchased from a local market in Karaj, Iran. They were visually Water Content: Wrapping material and cold storage inspected for freedom of defects and blemishes. Plums duration significantly (P 0.01) affected water content of were then wrapped in different wrapping materials plum (Table 1). The highest water content of 85.86% was (news paper + straw, kraft paper and kraft paper + straw), observed in kraft paper and lowest (85.05%) in news paper placed in plastic boxes and stored in cold storage at -1 C and wrapping material affected water content in the order temperature and 98% relative humidity for 0, 8, 16, 4 and of kraft paper > kraft paper + straw > news paper. 3 days. Also, the highest water content of 87.0% was observed in 0-day and lowest (83.83%) in 3-day and water content Water Content: The water content of plums was decreased with increased cold storage duration (Table ). determined using the equation (1): Moreover, interaction of wrapping material cold storage duration had no significant effect (P 0.01) on water Water content (%) = 100 (M1-M )/M 1 (1) content (Table 1). The study of wrapping material and cold storage duration combinations on water content Where: indicated that in each wrapping material, water content M 1 = Mass of sample before drying, g had the highest value in 0-day and the lowest value in M = Mass of sample after drying, g 3-day. In addition, the maximum mean value for water Fig 1: Handheld refractometer
Agric. Engineering Res. J., 5(1): 01-06, 015 Total Soluble Solids (TSS): Although wrapping material had no significant effect (P 0.01) on TSS of plum, cold storage duration significantly (P 0.01) affected it (Table 1). Anyway, the highest TSS of 14.39% was observed in kraft paper + straw and lowest (13.94%) in news paper and wrapping material affected TSS in the order of kraft paper + straw > kraft paper > news paper. Also, the highest TSS of 15.64% was observed in 4-day and lowest (13.00%) in 8-day and TSS frequently decreased and increased with increased cold storage duration (Table ). Moreover, interaction of wrapping material cold storage duration had significant effect (P 0.01) on TSS (Table 1). The study of wrapping material and cold Fig : Handheld fruit penetrometer or fruit firmness tester storage duration combinations on TSS showed that in kraft paper + straw, TSS had the highest value content (87.0%) was observed in 0-day of three wrapping (15.75%) in 16-day and the lowest value (1.75%) in 8-day. materials and the minimum mean value for water content Also, in kraft paper, TSS had the highest value (83.30%) was observed in 3-day of news paper. (15.75%) in 4-day and the lowest value (1.88%) in 8- Furthermore, water content in each wrapping material day. Besides, in news paper, TSS had the highest value decreased with increased cold storage duration (Table 3). (15.55%) in 4-day and the lowest value (13.13%) in 16- These results are in agreement with those of Mahmoud day. In addition, the maximum mean value for TSS and Savello [18], Avena-Bustillos et al. [19], Rashidi et al. (15.75%) was observed in 16-day of kraft paper + straw [0] and Rashidi et al. [1] who concluded that coatings, and 4-day of kraft paper and the minimum mean value for films and wrapping materials significantly conserved TSS (1.75%) was observed in 8-day of kraft paper + straw water content. These results are also in line with the (Table 3). These results are in agreement with those of results reported by Smith and Stow [4], Baldwin et al. [9], Smith and Stow [4], Rashidi et al. [0] and Rashidi et al. Rashidi et al. [0], Rashidi et al. [1], El Ghaouth et al. [5] who concluded that coatings, films and wrapping [], Bahri et al. [3] and Niari et al. [4] that water materials significantly affected TSS. However, these content significantly decreased with increased cold results are not in line with the results reported by storage duration. Park et al. [16, 17], Rashidi et al. [0], Bahri et al. [3], Table 1: Analysis of variance for some quality characteristics of plum (cv. Shablon) Mean square ------------------------------------------------------------------------------ Source of variation Degree of freedom Water content TSS Firmness Wrapping material 3.0 ** ns 1.0 5.90 ** Cold storage duration 4 19. ** 10.8 ** 44.9 ** Wrapping material Cold storage duration 8 ns 0.8.05 ** ns 0.71 Error 45 0.4 0.5 1.10 C.V. (%) --- 0.58 3.54 9.68 ** = Significant at 0.01 probability level ns = Non-significant Table : Means comparison for some quality characteristics of plum (cv. Shablon) for different studied treatments using DMRT at 1% probability Treatment Water content (%) TSS (%) Firmness (kg/cm ) Wrapping material Kraft paper + straw 85.39 b 14.39 a 11.16 a Kraft paper 85.86 a 14.16 ab 11.14 a News paper 85.05 c 13.94 b 10.1 b Cold storage duration 0-day 87.0 a 14.07 b 1.70 a 8-day 86.47 b 13.00 c 1.33 ab 16-day 85.0 c 14.17 b 11.57 b 4-day 84.47 d 15.64 a 9.61 c 3-day 83.83 e 13.94 b 8.337 d Means in the same column with different letters differ significantly at 0.01 probability level according to DMRT 3
Agric. Engineering Res. J., 5(1): 01-06, 015 Table 3: Means comparison for some quality characteristics of plum (cv. Shablon) for combinations of wrapping material and cold storage duration using DMRT at 1% probability Wrapping material Cold storage duration --------------------------------------------------------- Water content (%) TSS (%) Firmness (kg/cm ) Kraft paper + straw 0-day 87.0 a 14.07 bc 1.70 a 8-day 86.48 ab 1.75 f 1.65 a 16-day 85.15 de 15.75 a 1.41 a 4-day 84.43 efg 15.63 a 9.48 cde 3-day 83.70 gh 13.75 bcd 8.65 de Kraft paper 0-day 87.0 a 14.07 bc 1.70 a 8-day 87.03 a 1.88 ef 1.61 a 16-day 85.73 cd 13.63 cde 11.97 a 4-day 84.85 ef 15.75 a 9.885 cd 3-day 84.50 ef 14.50 b 8.558 de News paper 0-day 87.0 a 14.07 bc 1.70 a 8-day 85.90 bc 13.38 cdef 11.73 ab 16-day 84.73 ef 13.13 def 10.33 c 4-day 84.13 fg 15.55 a 8.470 de 3-day 83.30 h 13.56 cde 7.88 e Means in the same column with different letters differ significantly at 0.01 probability level according to DMRT Niari et al. [4], Rashidi et al. [5] and Hussain et al. [6] Toivonen [7], Rashidi et al. [0] and Rashidi et al. [7] that TSS significantly increased by increasing cold that firmness significantly decreased by increasing cold storage duration. storage duration. Firmness: Wrapping material and cold storage CONCLUSIONS duration significantly (P 0.01) affected firmness of plum (Table 1). The highest firmness of 11.16 kg/cm Wrapping material and cold storage duration was observed in kraft paper + straw and lowest (10.1 significantly (P 0.01) affected water content and kg/cm ) in news paper and wrapping material affected firmness of plum. Although wrapping material had no firmness in the order of kraft paper + straw > kraft significant effect (P 0.01) on TSS of plum, cold storage paper > news paper. Also, the highest firmness of duration significantly (P 0.01) affected it. Results of the 1.70 kg/cm was observed in 0-day and lowest study indicated that kraft paper for water content of (8.337 kg/cm ) in 3-day and firmness decreased with plums and kraft paper + straw for TSS and firmness of increased cold storage duration (Table ). Moreover, them were the best wrapping materials. In addition, water interaction of wrapping material cold storage duration content and firmness of plum decreased by increasing had no significant effect (P 0.01) on firmness (Table 1). cold storage duration, whereas TSS of plum frequently The study of wrapping material and cold storage decreased and increased by increasing cold storage duration combinations on firmness indicated that in duration. each wrapping material, firmness had the highest value in 0-day and the lowest value in 3-day. In addition, REFERENCES the maximum mean value for firmness (1.70 kg/cm ) was observed in 0-day of three wrapping materials and 1. Nazari, M. and M. Rashidi, 013. Prediction of the minimum mean value for firmness (7.88 kg/cm ) was plum mass based on some geometrical properties. observed in 3-day of news paper (Table 3). These results Middle-East Journal of Scientific Research, are in agreement with those of Lerdthanangkul and 14(10): 1337-1344. Krochta [15], Rashidi et al. [0] and Rashidi et al. [7]. Nazari, M., M. Rashidi and I. Ranjbar, 013. Modeling who concluded that coatings, films and wrapping of plum mass based on geometrical properties using materials significantly affected firmness. These results are linear regression models. American-Eurasian J. Agric. also in line with the results reported by Mostofi and & Environ. Sci., 13(4): 570-574. 4
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