| Summary: | 碩士 === 國立臺灣大學 === 園藝暨景觀學系 === 107 === In recent years, Taiwan''s elderly population has grown rapidly. In March 2018, the proportion of the elderly population exceeded 14%. It officially entered the aged society, and the market for senior consumers has also expanded rapidly. In terms of diet, chewing and swallowing disorders caused by age often appear on elderly. The difficulty in eating may lead to psychological burdens caused by uneven nutrition and dietary restrictions. Therefore, the development of foods with mouth comfort, color and flavor is the goal of advanced food development, and this study chooses the popular hard and crisp apples to be the material. The object of the study is to develop the new elderly food process and to soften the hard fruits and vegetables by the new process without thermal treatment, and the product will achieve UDF. At the same time, it will maintain its appearance and nutrients. This study is divided into two parts. The first part (Process A) firstly promotes commercial complex pectinase solution into apple slices by decompression and softens the material, and then applies high pressure processing to reduce enzyme activity and sterilization. Process A is finally adjusted. The condition is to add 0.05% of commercial complex pectinase solution in the amount of 1/3 slices , and then pack with vacuum-packing machine after depressure for 40 seconds, react at 4 ̊C for 1 hour, then applying 600 MPa for 10 minutes. The product can successfully reach the UDF "easy chewing" grade. This process is suitable for -20 ̊C freezing to inhibit the softening reaction. In terms of quality measurement, the L* value is significantly higher after high pressure processing at 600 MPa for 10 minutes. In the control group, the a* value was significantly lower in the control group, indicating that it could reduce the browning of the apple slices. The contents of reducing sugar, vitamin C, total phenol and total flavonoids were 91.71%, 134.44%, 132.64% and 119.36% of the control group, respectively. The DPPH antioxidant capacity was 169.35% of the control group, which showed that it not only avoided the loss of components, but also increased the release of the components. The hygienic test can effectively inhibit the growth of microorganisms and the Coliform. The test of Coliform was negative. Since the enzyme used in Process A is a complicated, it has the disadvantage of being difficult to control. Therefore, the second part adjusts the shortages of process A (Process B), and attempts to develop the process with a single pectinase. First, the polygalacturonase and pectin lyase are separately determined, including the activity at different temperatures, as well as the effect of heat and high pressure treatment on their activity, then develop the method based on the first part of the results and the characteristics of single enzymes. According to the results of enzyme assay, it can be known that 200 MPa can enhance the activity of pectin lyase. The final condition of Process B is to add 0.01% of the pectin lyase solution in the amount of 1/3 of the slices, and then pack with vacuum-packing machine after depressure for 40 seconds, then seal it, and then apply 200 MPa for 10 minutes to promote the enzyme reaction. It is reacted at 50 ̊C for 30 minutes, and finally sterilized by high pressure processing at 600 MPa for 3 minutes. This product can successfully reach the UDF “easy chewable” grade, and can inhibit the softening reaction during 4 ̊C storage to avoid the hardness decreasing. And the hygienic test can effectively inhibit the growth of microorganisms within 7 days, and the test for Coliform is also negative. The new process developed in this study is non-thermal through the process, not only retains its appearance and nutrition, but also takes short production time and provides ready-to-eat food. It has the potential to develop new elderly foods.
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