عنوان مقاله [English]
Potato with the scientific name Solanum tuberosum. L is a plant that is cultivated as an important crop in all countries and is known in the human diet as a source of carbohydrates, proteins, and vitamins. This product is native to South America and originally from Peru. Potato is the fourth crop in the food basket of the people after wheat, rice and corn, which sometimes replaces rice in Iran and is in the second place, which shows its importance in meeting the nutritional needs of the people. According to the reports of the Food and Agriculture Organization of the United Nations, the area under potato cultivation in Iran in 2019 was more than 164 thousand hectares and the harvest from this area was about 5.32 million tons. In the food industry, this product is converted into a variety of products such as baked potatoes, fried potatoes, potato chips, potato starch, dried fries and so on. Due to the increasing expectations for food products with high quality and safety standards, accurate, fast and purposeful determination of food characteristics is essential. In the potato crop, quality evaluation after the harvest stage seems necessary to provide a reliable and uniform product to the market, because the potato, like many other products, has a non-uniform quality and care during the harvest stage. - Be. In addition, food safety and desirability play an important role in the food industry and is directly related to people's health. In addition, a large part of the potatoes used in the processing industry, potatoes are stored, so given the importance of this food and the demand of the people throughout the year, only through optimal and long-term storage can meet the needs of applicants. Was responsive. Potatoes for the processing industry must have some requirements such as low sugar content, dry matter and high specific gravity, high antioxidants, light skin color and no germination. Stored potatoes may be sweetened, rotted, dehydrated, and sprouted during storage. Post-harvest storage conditions can cause changes in chemical composition and product quality. Therefore, the management of potato tubers is very important in all stages of production and storage. Potato changes in storage depend on the variety, storage conditions. Although potato storage is very necessary for domestic and industrial use, due to its chemical and physical changes in the warehouse, it should be said that the characteristics of high quality potatoes in commercial exchanges of this product include more than 70 to 80% of tubers. Light-colored, uniform, firm, no bruising, no scaling, no cracks, no insect damage, rot and greening. Post-harvest storage conditions can cause many changes in the chemical composition of the potato tuber, resulting in changes in the quality characteristics of the final product. Sugar and starch are the main components that are affected by postharvest metabolism in the potato tuber and may ultimately affect their texture, sensory and cooking properties. The quality of potatoes and, consequently, the quality of processed products, depends significantly on the cultivar and environmental conditions, both during the growing season and during storage.
First, potatoes were prepared in 5 different cultivars and stored at 4-10 ° C. Data collection included measuring sugar and carbohydrate levels during storage.
The sugar content of each sample was measured in three replications using a liquid refractometer available at Mohaghegh Ardabili University. To do this, first some water was taken from the samples and after pouring into the microtube, it was placed in a refrigerated centrifuge, and after rotating at a speed of 1800 rpm for 2 minutes, the impurities were deposited and the pure liquid was separated. After reaching ambient temperature, the liquid was placed on a refractometer and its sugar level was read in terms of brix.
The amount of carbohydrates in the samples was extracted using the equipment available in the central laboratory of Mohaghegh Ardabili University. This operation was performed by the Skigel method. Glucose was used to prepare the standard curve. Consecutive dilution of glucose Preparation and color development at 490 nm for different concentrations of glucose were controlled and one ml of distilled water was used as a blank. This standard curve was used to calculate the total concentration of carbohydrates in the samples.
For each sample, sampling was performed in three replications and the amount of absorption wavelength was obtained, then the amount of carbohydrates was calculated by placing the wavelength in Equation (1).
According to the analysis of variance table, the interaction effect of cultivar and storage period on potato sugar content was significant at 1% probability level. You can see the changes in the sugar content of potato cultivars along the storage valley in Figure 4. According to Figure 4, the highest amount of sugar is related to Sprite cultivar and the lowest amount is related to Jali cultivar. Meanwhile, the sugar content of Agria and Jeli cultivars was the same at the time of harvest. Also, after 1 month from the time of potato harvest, the sugar content of Agria and Marfona cultivars were equal and this equality continued until the end of storage period. The reason for the difference in sugar content between different cultivars is mainly related to the type of soil, fertilizer and toxin used. According to the chart, the amount of sugar in all 5 potato cultivars during the storage period first decreases and then with increasing storage period, the amount of sugar also increases.
According to the analysis of variance table, the interaction of cultivar and storage period on the amount of potato carbohydrates was also significant at the level of 1% probability. Carbohydrate variations of potato cultivars along the storage valley are shown in Figure 5. According to Figure 5, the highest amount of carbohydrates is related to Sante cultivar and the lowest is related to Marfona cultivar. Also, at the end of the storage period, Marfona and Agria cultivars had the same amount of carbohydrates. As you can see, the amount of potato carbohydrates has decreased over time and with increasing storage time. Among these cultivars, the carbohydrate content of Marfona and Agria cultivars was higher than other cultivars. Also, carbohydrate changes during storage were almost linear in the three cultivars Sante, Agria and Marfona.