5:2 (2016) Journal of Food Engineering and Technology Effects of Different Transportation Methods on Quality of Sweet Cherry After Forced-air Cooling Xiaofang Zhang 1, 2, Sheng Liu 1 *, Li-e Jia 1, Lijun Sun 1, Yan Li 1 1. Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, National Engineering Research Center for Vegetables, Beijing, 100097, PR China 2. Shanghai Ocean University, Shanghai, 201306, PR China E-mail:zxf19910518@163.com Abstract: After harvest, core temperature of sweet cherry was decreased from 27 to about 3 by the forcedair cooling, and then they were seemingly transported by using three different methods, including the 0 transportation in plastic clamshell containers with a carton box packaging, the cooler box transportation at normal temperature, and the polystyrene foam box added ice bottle transportation. The result showed that the core temperature of sweet cherry with the polystyrene foam box added ice bottle transportation increased from 3 to near ambient temperature 28.91 in 40 hours, and the core temperature of sweet cherry with cooler box transportation only increased from 3 to 13.79 after 3 days. The evaluation and weight loss of sweet cherry with a polystyrene foam box and cooler box were 6.2, 5.17% and 7.7, 0.42% after 3 days transportation. Compared with other two transportation methods, the sweet cherry with 0 transportation had lower weight loss, respiration rate and ethylene release rate and higher firmness and higher content of soluble solid, titratable acid and vitamin C, and the date were 0.36%, 50.84 mgco 2 kg -1 h -1, 0.058 ulkg -1 h -1, 2.87 kg cm -1, 21.4%, 0.75%, 168.87 mg.100-1, and the sensory evaluation still kept at 8.5. Keywords: Sweet Cherry; Forced-air Cooling; Transportation; Quality. 1. Introduction Sweet cherry (Prunus avium L.) is one of the most appreciated fruit by consumers because of its good taste and rich nutritious. However, due to a high respiratory activity, minimal reserve carbohydrate, and high susceptibility to mechanical damage, sweet cherry loses its quality quickly in the hot harvest season [1]. The quality is usually determined by fruit skin colour, stem colour, flavor, sweetness, sourness and firmness, as these attributes have been found to be closely related to consumers acceptability and market prices[2]. Therefore, the sweet cherry need rapid elimination of field heat after harvest and low temperature control during storage and transportation [3]. Temperature is one of the most important factors in minimizing the postharvest life of sweet cherry. Higher temperature resulted in higher weight loss, respiration rates and lower firmness, and lower fruit quality. Yan studied the respiration rate of ( Bing ) sweet cherry at 20 was about 17.8 ug CO 2 kg -1 s -1 and at 0 was about 1.8 ug CO 2 kg -1 s -1, and a strict temperature control is extremely important for reducing catabolic activity and maintaining quality of sweet cherry during storage and transportation[4]. Important considerations of sweet cherry in long-distant transportation are suitable temperature and packaging. Particular interest has been shown in the cold chain transportation which is considered as a relatively safe method to extend their shelf-life and maintain high quality [5,6]. In this paper, the sweet cherry after harvest were cooled to 3 by the forced-air cooling, and then seemingly transported using three different methods, including the 0 transportation in plastic clamshell containers with carton box packaging, the cooler box transportation at normal temperature, the polystyrene foam box added ice bottle transportation. In order to determine the effects of different transportation methods on the postharvest transportation quality attributes of sweet cherry, the quality changes in sensory evaluation, weight loss rate, firmness, respiration rate, ethylene production rate and content of soluble solid, titratable acid and vitamin C were measured. 2. Materials and methods 2.1 Materials and treatments Xianfeng sweet cherry at 9 mature with healthy greenish peduncles were hand-harvested in the morning from 32
Journal of Food Engineering and Technology 5:2 (2016) tongzhou city in Beijing, China on 12th June 2016 and immediately transported to laboratory in 2 hours(h). There, fruit were selected for uniformity of size, ripeness, and absence of physical injuries or infection, and the core temperature of sweet cherry was decreased to 3 by forced-air cooling. After cooled, the sweet cherry was transported 3days(d) with three different methods, including the 0 transportation in plastic clamshell containers with carton box packaging, the cooler box transportation at normal temperature, and the polystyrene foam box added ice bottle transportation. 2.2 Sensory evaluation A trained panel consisting of 3 people evaluated the sensorial quality of the samples. Visual quality of sweet cherry was scored on a 9 to 1 scale, where excellent, freshly = 9;very good = 7; good, limit of marketability = 5; fair, limit of usability = 3 and poor, unusable = 1, where 6 is considered the minimum for salability[7]. 2.3 The weight loss Weight loss was measured according to the following formula: Weight loss (%) = (initial weight-final fruit weight after storage) 100/ initial weight. 2.4 Firmness Firmness of sweet cherry was measured in a 6 mm probe with a digital force gauge (FT-02, Facchini, Italy). 2.5 Respiration rate and ethylene production rate Respiration rate was determined using an infrared CO 2 analyzer, according to the method of Zhao et al [8]. Ethylene production rate was measured by gas chromatograph Agilent 7820A, according to the method of Li et al [9]. 2.6 Total soluble solid (TSS) and titratable acidity (TA) TSS content of fruits were determined by Atago PR-100 refractometer (Atago Co.Ltd., Tokyo, Japan) at room temperature. TA content of sweet cherry was titrated with 0.05 mol/l NaOH to the point of ph 8.1. Volume of NaOH was recorded and percent TA was calculated [10]. 2.7 Vitamin C (Vc) Vitamin C content was determined by a molybdenum blue colorimetric method [11]. 2.8 Statistical analysis Statistical analysis was done by statistical product and service solution (SPSS 13.0). The data obtained from each treatment of differences during storage were analyzed by analysis of a variance (ANOVA) test and then the least significant difference (LSD) test (P<0.05). 3. Results and discussion 3.1 Effects of different transportation methods on temperature of sweet cherry in transportation The average environment temperature of sweet cherry in the whole transportation process was 28.89 (Fig. 1). The core temperature of sweet cherry with polystyrene foam box added ice bottle transportation and cooler box transportation at normal temperature increased gradually, and the increase speed of former significantly greater than the latter. Before transportation, the core temperature of sweet cherry was decreased to 3.1. After 10hs transportation, the core temperature of sweet cherry in cooler box was 3.45, while the core temperature of sweet cherry in polystyrene foam box increased to 22. After 40hs transportation, the core temperature of sweet cherry in polystyrene foam box was reached to the environment temperature 28.91. After 3ds transportation, The core temperature of sweet cherry in cooler box was only increased to 13.97. 33
5:2 (2016) Journal of Food Engineering and Technology 30 Temperature ( ) 25 20 15 10 Environment temperature Cooler box environment temperature Core temperature of sweet cherry in cooler box Polystyrene foam box environment temperature Core temperature of sweet cherry in polystyrene foam box 5 0 8 16 24 32 40 48 56 64 72 Time (h) Figure 1 Effects of different transportation methods on temperature of sweet cherry in transportation 3.2 Sensory evaluation and weight loss Fig. 2 showed that the sensory evaluation score of sweet cherry decreased and the weight loss increased for all transportation methods. After 3ds transportation, the sensory evaluation of sweet cherry with 0 transportation and cooler box transportation were 8.5 and 7.7, and still above the threshold (6.0) of marketability, and the weight loss was 0.36% and 0.42%, respectively. Meanwhile, the sensory evaluation and weight loss of sweet cherry with polystyrene foam box was 6.2 and 5.17%, that the sweet cherry was not suitable for transportation and long-time retailing. The 0 transportation was the best method to maintain higher sensory evaluation and reduce the weight loss among the three transportation methods. Sensory evaluation (Score) 9 8 7 6 Weight loss (%) 6 5 4 3 2 1 0 1 2 3 Figure 2 Effects of different retailed methods on sensory evaluation and weight loss of sweet cherry 3.3 Firmness The firmness of sweet cherry decreased gradually during transportation time (Fig. 3). After 3ds transportation, the firmness of sweet cherry with 0 transportation, cooler box transportation and polystyrene foam box from initial value 2.93 kg cm -1 decreased to 2.87 kg cm -1, 2.7 kg cm -1 and 2.2 kg cm -1, respectively. The results showed that significant differences were found among the three transportation methods (P<0.05), and 0 transportation was the best to control the decline of firmness. 34
Journal of Food Engineering and Technology 5:2 (2016) Firmness (kg.cm -2 ) 3.5 3.0 2.5 2.0 1.5 Figure 3 Effects of different transportation methods on firmness of sweet cherry 3.4 Respiration rate and ethylene production rate The respiration rate and ethylene release rate of sweet cherry gradually increased with the increase of temperature (Fig. 4). The initial value of respiration rate and ethylene release rate were 45.73mgCO 2 kg -1 h -1 and 0.053 ulkg -1 h -1, respectively. After 1d transportation, the core temperature of sweet cherry with 0 transportation, cooler box transportation and polystyrene foam box were 2, 5.3, 25.6, and the respiration rate were 46.46, 54.18, 130.22 mgco 2 kg -1 h -1, respectively, the ethylene release rate were 0.056, 0.06, 0.12 ulkg - 1 h -1, respectively. After 3ds transportation, the core temperature of sweet cherry with cooler box transportation and polystyrene foam box transportation increased to 15.9 and 29.3, the opposite respiration rate were 96.05, 217.34 mgco 2 kg -1 h -1, and the opposite ethylene release rate were 0.07, 0.16 ulkg -1 h -1, respectively. Meanwhile, the respiration rate and ethylene release rate of sweet cherry with 0 transportation was only 50.84 mgco 2 kg - 1 h -1 and 0.058 ulkg -1 h -1. The results showed that 0 transportation was better to decline the respiration rate and ethylene release rate of sweet cherry than other two methods (P<0.05). Respiration rate (mg CO 2.kg -1.h -1 ) 240 200 160 120 80 40 Ethylene release rate (ul kg -1.h -1 ) 0.15 0.12 0.09 0.06 0.03 Figure 4 Effects of different transportation methods on respiration rate and ethylene release rate of sweet cherry 3.5 TSS and TA Fig. 5 showed the changes of TSS and TA content of sweet cherry in different transportation treatments, and Significant differences (P<0.05) were observed among the three methods. After 3ds transportation, the TSS content of sweet cherry with 0 transportation, cooler box transportation and polystyrene foam box decreased from initial value 21.83% to 21.4%, 20.33% and 19.1%, respectively. Meanwhile, the TA content of sweet cherry decreased from initial value 0.79% to 0.75%, 0.7% and 0.64%, respectively. 0 transportation samples were obtained higher value of TSS and TA content of sweet cherry. The result indicated that low temperature transportation was helpful to control the decline of TSS and TA content of sweet cherry. 35
5:2 (2016) Journal of Food Engineering and Technology 20 0.8 TSS (%) 16 TA (%) 0.6 12 0.4 Figure 5 Effects of different transportation methods on TSS and TA content of sweet cherry 3.6 Vitamin C content Vitamin C is one of the indexes of anti-aging. Fig. 6 showed that the content vitamin C of sweet cherry with three treatments decreased with the extension of transportation time. After 3ds transportation, vitamin C content of sweet cherry with 0 transportation, cooler box transportation and polystyrene foam box were 168.87, 134.66, 92.89mg 100-1, respectively, decreased 7.25%, 26.04% and 48.98%, respectively. The results indicated that low temperature transportation effectively inhibited the decline of vitamin C content and maintained good quality (P<0.05), and the 0 transportation was the optimum method of sweet cherry. Vc content (mg.100g -1 ) 180 150 120 90 60 Figure 6 Effects of different transportation methods on Vitamin C content of sweet cherry 4. Conclusions After 3ds cold chain of transportation, the core temperature of sweet cherry with cooler box transportation and polystyrene foam box were 13.97 and 28.91, 0 transportation still maintained lower core temperature of sweet cherry. During transportation, the sensory evaluation, weight loss, firmness, respiration rate, ethylene release rate and the nutrition content were significantly affected by temperature. After 3ds transportation, the optimum method of sweet cherry was the 0 transportation, and the date of sensory evaluation, weight loss, firmness, respiration rate, ethylene release rate and the content of soluble solid, titratable acid, vitamin C were 8.5, 0.36%, 2.87 kg cm - 1, 50.84 mgco 2 kg -1 h -1, 0.058 ulkg -1 h -1, 21.4%, 0.75%, 168.87 mg 100-1, respectively. 5. References [1]Suwimol, C., John, B.G., Golding, Q. V., Vuong, K. P., Costas E. S. Sweet cherry: Composition, postharvest preservation, processing and trends for its future use. Trends in Food Science & Technology, 2016, 55: 72-83. [2]Dever, M. C., MacDonald, R. A., Cliff, M. A., & Lane, W. D. Sensory evaluation of sweet cherry cultivars. HortScience, 1996: 31, 150-153. [3]Kupferman, G., Sanderson, P. Temperature management and modified atmosphere packing to preserve sweet cherry fruit quality. Acta Hort, 2001, 667: 523 528. [4]Yan, W., Lynn, E. Respiration and quality responses of sweet cherry to different atmospheres during cold storage and shipping. Postharvest Biology and Technology, 2014, 92: 62-69. 36
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