ผลของวิธีการทำแห้งต่อสมบัติทางเคมีกายภาพและคุณค่าทางโภชนาการของมันเทศแผ่นบางและแป้งมันเทศ
ชื่อผู้แต่งข้างต้นเป็นข้อความจากระเบียนผลงาน ไม่ได้ผูกกับรหัสนักวิจัย จึงกดดูผลงานอื่นของบุคคลนี้ไม่ได้ — ในคลังนี้ 142,080 ผลงาน (63.6% ของทั้งหมด) มีชื่อผู้แต่งที่เชื่อมกับหน้าผู้แต่งได้ และ 60,298 ผลงาน (27.0%) มีผู้แต่งที่ผูกกับรหัสนักวิจัยจริง ส่วนอีก 81,382 ผลงานไม่มีข้อมูลผู้แต่งเลย (มีชื่อผู้แต่งเป็นข้อความอยู่ 142,009 ผลงาน = 63.5%)
บทคัดย่อ
Sweet potato (SP) cultivars with deep purple (65-3) and orange-fleshed (T101) colors newly developed by Agriculture Development and Research Center, Phichit, Thailand were studied. They contain nutritious benefits and functional pigments, including flavones, phenolic acids, B-carotene and anthocyanin. However, fresh SP roots are bighly perishable and difficult to store. To reduce postharvest losses and extend their uses, fresh SP roots could be converted into flour. This study aimed to investigate the influence of drying methods on physico- chemical properties, anthocyanin, B-carotene and antioxidant activity retentions of purple and orange-fleshed sweet potato flours (SPFs). Fresh SP roots were peeled, cut into 2 mm thick slices, and pretreated by soaking in 0.5% sodium metabisulphite for 5 min, then dried in the hot air oven (50-80?C). For drum drying process, the pretreated sweet potato slices were steamed at 100 *C, blended and fed to the drum dryer at 80-110?C and 3-7 rpm drum speed. The dried sweet potato slices and flakes were grinded into powder and sieved through 80 mesh sieve. Drying processes significantly enhanced anthocyanin contents of SPFs by 1.8 to 3.8 times (dry basis). Higher percentage losses of B-carotene occurred during hot air drying than drum drying due to longer processing times. Purple-fleshed SPFs prepared by drum drying contained higher total phenolic contents than those prepared by hot air drying for their higher anthocyanin retentions. Antioxidant activity (DPPH assay) of SPFs decreased after drying processes. Water absorption of drum dried and hot air dried SPFs ranged from 4.4 to 6.4 and 2.9 to 4.5 gg flour, respectively. Swelling power and solubility of SPFs increased as a result of drying. The optimal conditions for drum dried and hot air dried SPF manufacture were 95?C at 3-5 rpm and 60-70*C, respectively, based on anthocyanin, B-carotene, total phenolic, antioxidant activity, and color retentions. Pasting temperatures. of hot air dried orange-fleshed SPFs (84-850C) were slightly higher than those of purple-fleshed SPFs (80 - 83*C). Drum drying process produced pre-gelatinized (instant) SPFs as indicated by RVA and DSC results. Developed SPFs could be utilized in a variety of foods to meet a growing demand in the health food markets such as natural food colorants, bakery and snack products, noodles, confectioneries and beverages. len