The effect of shape, blanching methods and flour on characteristics of restructured sweetpotato stick

Abstract

The blanching methods and controlling dry matter content used in the preparation of mashed sweetpotato (SP) for producing restructured sweetpotato stick (RSS) were studied. The two shapes of trimmed tuber were sliced and diced. Blanching was conducted by (i) boiling for 2 min in water at 100°C and (ii) blanching in water at 100°C containing 1% (w ⁄ v) sodium tripolyphosphate (STP) for 2 min. Controlling the dry matter content of dough was conducted by adding SP flour (0%, 5%, 10%, 15% and 20%). Chemical and physical characteristics were determined on the final product. The results from this study showed that blanching in 1% STP for 2 min improves colour and ash content of fried stick. Mixing of 5% SP flour with mashed SP produces suitable dough for further processing. RSS can be produced by a combination of blanching in 1% STP and mixing with 5% SP flour produce an intermediate hardness, high lightness and low redness colouration of RSS.

Determination of citric acid pretreatment effect on nutrient content, bioactive components, and total antioxidant capacity of dried sweet potato flour

“…The lowest (2.4–2.6%) was from SPK00/06, SPK004/6/6, Guntute, and Bucteca varieties treated in 1% CA and dried at 65°C. The variation observed in terms of protein contents may be due to varietal difference or nonenzymatic browning due to condensation of reducing sugars with amino groups due to Maillard reaction (Utomo et al., ). In terms of crude protein, the observed values are comparable with other root crops, such as cassava and yam (Grabowski, Truong, & Daubert, ).…”

“…Dehydration could be an inexpensive technology that can be easily adapted to reduce the losses and improve its utilization in food formulations. Proper drying of OFSP can result in a stable product with better quality (Utomo, Man, Yaakob, Rahman, & Saad, 2008) when assisted with predrying treatments. Singh, Raina, Bawa, and Saxena (2003) used potassium metabisulfite and sodium chloride to improve the quality of chips from sweet potato.…”

Effect of pretreatments and drying temperatures on sweet potato flour

“…To reduce the drying time and retain the quality of fruits and vegetables, various pretreatment methods (chemical, thermal and physical) have been investigated (Chen et al. , 2005; Utomo et al. , 2008).…”

“…The relatively cheaper hot air-drying is commonly used in food production, but the longer drying time usually results in inferior product quality. To reduce the drying time and retain the quality of fruits and vegetables, various pretreatment methods (chemical, thermal and physical) have been investigated (Chen et al, 2005;Utomo et al, 2008). Sulphites can reportedly cause health problems such as asthmatic reactions in sensitive individuals (Van Hall, 2000).…”

“…Several methods have been developed to eliminate discolouration. Utomo et al (2008) and Mais & Brennan (2008) used blanching with sodium tripolyphosphate (Na 5 P 3 O 10 ) and sodium metabisulphite (Na 2 S 2 O 5 ) respectively to eliminate discolouration in flour preparation from sweet potato. Sweet potato roots can be processed into products with longer shelf life and improved characteristics.…”