Optimization of Extraction of Protein Isolate From Papaya Seeds and Their Applications on Salad Dressing Product

• Main Authors: Pin-Xiu Guo, 郭品秀
• Other Authors: Ya-Ling Huang, Ph.D.
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/52419517817560684389

碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 101 === Papaya (Carican papaya) seeds are the wastes that come from being eaten fresh or processed papaya. Proximate compositon in dry weight showed that papaya seed contains 33.1% of lipid and 26.2% of protein. If the wastes can be further developed into useful products, it can increase the added-value of agricultural and enchance economic efficiency. Response surface methodology, (RSM) was emplooyed to evaluate the optimized parameter for maximum protein extraction from papaya seeds.The result was as follows: NaCl solution concentration, 1.5 M; solute:NaCl solution ratio=1:40 (w/v); extraction time, 2 h. The recovery of 94.8% of papaya seed protein was obtained and isoelectric point was determined as being pH 4.8. The functional properties of commercial soy protein isolate (SPI) and papaya protein were determined for comparison. The papaya seed protein had a poorer solubility and water-holding capacity at the pH 7.0 and 25C than SPI, but oil holding capacities, emulsifying activity, foaming capacity and foaming stability of papaya seed protein were higher than those of SPI. Furthermore, emulsifying properties of PSP as a function of concentration (0.5%、1.0%、1.5%及2.0%) and pH (3.0、4.0、5.0及6.0) were studied and their emulsifying capacity, emulsion viscosity, droplet distribution and emulsion type were compared. The results demonstrated that PSP had the higher emulsifying capacity at pH 3.0 than that at pH 5.0. In the range of PSP concentration of 0.5%2%, the emulsifying capacity was highest with 1.0% PSP. Referring to viscosity and stability of emulsion, they exhibited to be excellent at pH 3.0, regardless of concentration. While at pH 5.0,the emulsion had very poor viscosity and bad stability. Droplet distribution of emulsion is better with more stable emulsion, giving an emulsion with droplet size of less than 100 μm. Replacement of PSP for egg yolks was prepared for French salad dressing and was compared with conventional one (adding 0.6% egg yolks) on the sensory evaluations, viscosity, stability and microbial growths. The result showed that among the all groups, the added with 1.0% PSP had poor performance.While added with 1.0% PSP group had slightly high acceptability on mouthfeel, flavor and sour than traditional salad dressing. However, the color acceptance for added with 1.0% PSP group than was much worse than that for traditional one.