Physico-chemical and mechanical properties of Shallot onion for designing of processing equipment and packaging

Aggregatum onion (Allium cepa L. var. aggregatum.) is used as seasoning material for preparation of food. In south Indian cuisine, it is primarily renowned for its pungency and used in various dishes. By secondary processing different product could be prepared from peeled onion are flakes, powder and paste. Now a days the demand for Ready to cook (RTC) products are high in the market. In order to understand product behaviour during design of processing equipment, grading, packaging, and storage for peeled onion. The physico-chemical and mechanical properties are important. These properties were measured as per the standard procedures. The true density and bulk density of aggregatum peeled onion were 989kg/m3and 378 kg/m3 respectively. The coefficient of static friction, crushing load and penetration load were also measured. The average crushing load and penetration load of fresh peeled onion were recorded as 107.35 and 8.69 N respectively. The moisture content and shape of aggregatum peeled onion was measured as 83.23% (w.b) and spherical in shape. The TSS of fresh peeled onion was found 14.45 ± 2.47° Brix. The pH, acidity were also measured. The ascorbic content, total phenolic and antioxidant activity DPPH % were found as 16.44 ± 0.28 mg/100gm, 1295 µg GAE/g FW and 67.5% respectively.