Document Type : Research Paper - Pomology
Authors
1 Department of Horticulture, Faculty of Agronamy Sciences, Sari Agricultural sciences and Natural Resources University (SANRU), Sari, Iran
2 Dep. of horticultural sciences, SANRU, Iran
3 Dep of Horticulture, Faculty of Agronamy Sciences, Sari Agricultural sciences and Natural Resources University (SANRU), Sari, Iran
4 Assistant Professor, Department of Horticultural Science, Imam Khomeini International University, Qazvin, Iran
Abstract
Background and Objectives: Blackberries due to the lack of protective layer or cuticle, are sensitive to decay and weight loss wrinkle after harvest. Therefore, blackberry have a short life and long-term storage of blackberry is difficult. For this reason, in this study, the effect of pre-harvest treatments on the shelf life of thornless blackberry was investigated.
Materials and Methods: This experiment was conducted in 2020 as a factorial in the form of a completely randomized design with two factors in three replications. The first factor consisted of nutritional treatments at five levels (control, calcium nitrate 5 g/L, potassium silicate 1 g/L, calcium nitrate 5 g/L + potassium silicate 1 g/L, and potassium fertilizer 51-0-0 with a concentration of 3.5 g/L) which applied in stage fruitset. The second factor was storage time in cold storage(4 ͦC) at four levels (0, 6, 12 and 18 days post harvesting). Qualitative traits (percentage of weight loss and firmness of the fruit), sensory quality (pH of the extract, soluble solids, taste index, ascorbic acid), nutritional value (total phenol and anthocyanin), and sensory evaluation (marketability, taste, and color of the fruit) were examined.
Results: The results indicated during the storage period of blackberry, the weight loss of the berry showed an increasing trend. The combined treatment of calcium nitrate and potassium silicate significantly reduced berry water loss on the eighteenth day. This treatment also managed to maintain the highest berry firmness (0.21 N) during storage, whereas a decrease in firmness was observed with an increase in storage time. Berry length and width decreased with increased storage time, with the highest values obtained in the control treatment (2.107 and 1.923 centimeters, respectively). The levels of soluble solids and taste index increased from harvest to the twelfth day, with the highest amounts (9 and 4.22, respectively) obtained in the potassium silicate treatment. Also, the examination of the amount of ascorbic acid showed that during the storage period of blackberry, its amount in the control treatment increased until the sixth day and then decreased until the end of the storage period. The application of potassium silicate led to a significant preservation (P≤ 0.05) of vitamin C compared to other treatments during storage, with 9% of vitamin C observed in this treatment on the eighteenth day. The highest amount of phenols during storage, with the application of calcium nitrate and potassium silicate, was 74.75 mg/g gallic acid of fruit extract. Based on the results, fruit anthocyanin also showed the highest amount (189.8 mg cyanidin 3-glucoside per liter of juice) in the combined treatment of calcium nitrate*potassium silicate on the day of harvest.Finally, the sensory parameter evaluation showed that fruit quality decreased with increased storage time, along with a reduction in consumer preference. Among pre-harvest treatments, potassium treatments were found to be more effective.
Discussion: The overall results have shown that using a combined treatment of calcium nitrate and potassium silicate increases the firmness of fruit during storage. Additionally, potassium silicate has a positive impact on the soluble solid content and fruit taste index, and it can help preserve vitamin C in the fruit. The use of calcium nitrate and potassium silicate enhances the levels of phenols and anthocyanins in the fruit. While the quality of the fruit may decrease with longer storage time, the use of nutritional treatments can assist farmers and fruit sellers in improving storage and enhancing the quality of their products.
Keywords
Main Subjects
)