The Characteristic Change of Shallot (Allium ascalonicum L.) During Curing Process

The objectives of this research were to study changes in the characteristics of shallot (Allium ascalonicum L) during curing prosess at a temperature of 45ºC ± 0,6ºC, and RH 69% ± 0,4%. The study was consisted of 2 stages: calibration of temperature and RH in cabinet drier and Study of physical and chemical characteristics changes of red onions during curing process at selected temperatures. Research method used was experimental method with descriptive analysis followed by regression and correlation analysis. Curing time in a cabinet dryer was varied as follows; 0 hours, 32 hours, 80 hours, 92 hours, and 104 hours. Observations were conducted at curing includes tuber water content, water content of the outer shell, VRS levels, levels of total dissolved solids, tuber hardness, neck diameter, decrease weight, color of the outer shell and sensory characteristics of the bulbs, tubers neck, and outer shell. The results showed that the curing of shallot in a cabinet dryer at a temperature 45ºC ± 0,6ºC, and RH 69% ± 0,4% by adjusting the temperature controller on the cabinet dryer at position 47°C produce bulbs with a good outer skin apparance. During curing process, quality of the onion bulb was improved as indicated by increased the size of the bulb diameter, tubers hardness, levels of dissolved solids, the intensity of red color at tuber skin, levels of VRS, with a reduction in root neck diameter, and decrease water content of the outer shell. This condition was marked also by dry out the outer shell and neck bulbs. Onion dried in a cabinet dryer at a temperature of 44.5 ± 0.6 ° C and RH 59.8 ± 0.8% for 92 hours produced tubers with the best quality during curing. Characteristics of the tuber for this treatment are : water content 79.92% V / B; water content of the outer shell 56.80% V / B; neck diameter of tuber 2:21 mm; tubers hardness 3.60 Kg / m2; tuber diameter 36.49 mm; levels of dissolved solids 19:44%; Sucrose, red color intensity of tuber skin (a *) 29.28, VRS 33.65 μgrek / g; decreasing weight of 14.23 % wb; and are characterized by dried out the outer shell and neck bulbs