Influence on the qualities of microencapsulated sweet potato leaves powder by high and low temperature spray-drying process

• Main Authors: Chien-Pin Lai, 賴建賓
• Other Authors: Chi-Ching Yang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/75541937826944458164

碩士 === 國立屏東科技大學 === 食品科學系所 === 98 === Sweet-potato leaves is a fast-growing and with rich nutrient plant and can be yielded throughout the year without using pesticides. Because of the overproduction and limiting by the storage life, sweet-potato leaves used to be the feeding stuffs in the rich phase thus the problem is need to be solved by such as food processing method. However, the chlorophyll degradation usually results in the undesirable color deterioration during green vegetables (such as sweet-potato leaves) processing or storage. To solve this problem, in this study, different spray-drying temperatures were selected and to prepar sweet-potato leaves microencapsulated powder (SL-MP) by microencapsulation technology and use Taguchi method to search the optimum combination of core and wall material and processing condition. Finally, we also investigate the SL-MP storage stability and test the feasibility of adding it to frankfurter sausage. By Taguchi's method, we could obtain the optimization conditions to produce low temperature spray-drying sweet-potato leaves microencapsulated powder (LTSSL-MP) and high temperature spray-drying sweet-potato leaves microencapsulated powder (HTSSL-MP), and the microencapsulation efficiency and yield of LTSSL-MP were respectively 11% and 9% and higher than HTSSL-MP. The optimal processing conditions of LTSSL-MP and HTSSL-MP could be obtained via statistical analyses. The verified experiments were conducted to authenticate selected factors and the results exhibited high agreement between predicted S/N ratios and verified values. The coating effect of LTSSL-MP and HTSSL-MP was analyzed by testing their solubility in water. Results revealed that the upper layer liquid color of LTSSL-MP was pale yellow and more transparent than HTSSL-MP; moreover, the upper layer liquid color of sweet-potato leaves powder without microencapsulation (SLPWM) was shown the opaque green color (chlorophyll leaching). In storage experiment, the LTSSL-MP and HTSSL-MP stored under light resistant condition at room temperature (25℃) for 4 months, the LTSSL-MP and HTSSL-MP also still respectively contained 78 and 75% of chlorophyll retention percentage and 36 and 31% of total antioxidant capacity after storage. No significant difference was found between LTSSL-MP and HTSSL-MP. The storage stability of LTSSL-MP and HTSSL-MP were two times higher than the SLPWM (37% and 16% of chlorophyll reduction, respectively). For steam and roast experiment of frankfurter sausages which added LTSSL-MP, HTSSL-MP and SLP, respectively. The heat-tolerance of color was: LTSSL-MP > HTSSL-MP > SLPWM. The TBA value of frankfurter sausage added SL-MP and SLPWM was significant lower than blank (P < 0.05). The sensory evaluation indicated that aroma of frankfurter sausage added 2.5% HTSSL-MP was higher than marketed frankfurter sausage and no significances in springiness, juiciness and overall acceptance (P > 0.05).