| Summary: | 碩士 === 大仁科技大學 === 食品科技研究所 === 102 === Sufficient dietary fiber uptake promotes gastrointestinal mobility, and prevents cardiovascular diseases, obesity, etc. Considering that people nowadays are busy and have lots of opportunities to dine out, insufficient dietary fiber is a general concern. Lemon are one of the primary fruits in Taiwan,and there are a lot of lemon pomace (LP) remaining after the process of manufacturing juice. Lemon pomace is rich in Physicochemical, such as dietary fibers and polyphenols. Therefore, by examining the physiochemical properties and analyzing the antioxidant compounds of LP, this study is to investigate the prerequisite processing condition of lemon pomace fibers (LPF) and furthermore its feasibility on toast applications.
Results showed that drying procedures of LP and LPF under different temperatures did not generate significant differences in total flavonoids capacity and DPPH radical scavenging capacity between LP and LPF. Total flavonoids capacity and DPPH radical scavenging capacity of the former (LP) were about 27.55-32.12 mg/g and 2.44-2.91 mg Trolox/g, and those capacities of the latter (LPF) were about 2.18-2.27 mg/g and 0.45-0.52 mg Trolox/g. However, total polyphenol capacity of LP and LPF were higher at 90℃ drying temperature, which were 5.80 and 1.41 mg/g, respectively Moreover, the water retention capacity and swelling property of LP and LPF were higher at 45℃.The water retention capacity and swelling property of LP were 7.08 and 11.22 mL/g and those of LPF were 12.23 and 15.65 mL/g, respectively. Considering the drying rate and higher content of total polyphenol retained of LP, this study chooses 90℃ as its drying temperature.
Among six different partical sizes of LPF (840~420, 420~250, 250~177, 177~149, 149~104 and 25 μm), smaller LPF had better water retention capacity, oil retention capacity and swelling property than larger ones, but larger LPF had superior amounts of total polyphenols, total flavonoids and antioxidant capacity than smaller ones. Hence this study chooses larges size of LPF (840~420 μm) as the raw material for toast preparation in order to preserve greater antioxidant capacity.
The analysis of methanol or water extract from toasts showed that the levels of total polyphenols or DPPH radical scavenging capacity were increased significantly by the addition of LPF; however, the cohesiveness, springiness and specific volume of toast were decreased accordingly. Furthermore, preference sensory evaluations (i.e., the appearance, taste, texture or overall preferences) of toast with 3% LPF where not significantly different from control toast However, toasts with 6% and 9% LPF exhibited worse taste, texture and overall preferences than control.
The above study revealed that LPF has good water holding capacity and swelling property, as well as high Physicochemicals and antioxidant capacity. Therefore, LPF can be applied properly as a health food material in the future.
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