棠梨果汁貯藏過程中品質的變化

Studies of Quality Changes on Tang Li (Pyrus pyrifolia var. culta) Juice during Storage Period

林麗芳(Lih-Fang Lin)

《桃園區農業改良場研究報告》 4期 (1987/05) Pp. 10-22

https://doi.org/10.29567/ZHWHGX.198705.0002

摘要

本試驗係以化學及儀器分析方法配合官能品評，探討棠梨果汁貯藏過程中品質的變化情形，並於果汁中添加抗氧化劑，羧甲基纖維素及控制貯藏條件以防止貯藏期間品質的劣變。結果顯示棠梨果汁貯藏期間pH值及可溶性固形物含量降低，而可滴定酸度、可溶性單寧含量及多酚氧化酶活性增加。以官能品評配合色差計讀值顯示果汁的色澤在貯藏過程中漸呈黃褐色、風味、香氣、口感的感官接受性漸差。貯藏期間有機酸分佈的層析圖形均相似，但總有機酸及檸檬酸含量在貯藏過程中略增加，而蘋果酸、酒石酸及抗壞血酸含量的變化差異不顯著。棠梨果汁貯藏於低溫品質劣變較室溫慢，光照對品質的影響差異不明顯。使用2%的維生素丙可有效防止果汁貯藏期間褐變的發生，此外，添加0.5%的羧甲基纖維素可以避免果汁貯藏過程中發生沈澱分層的現象。

並列摘要

This study was conducted by combining chemical and instrumental analysis with organoleptic evaluation to investigate the changes in quality of Tang-li juice during storage period. Antioxidant, carboxymethyl cellulose and controlling storage conditions were used to prevent quality from getting worse. The result showed that pH value and soluble solids content were decreasing. However, the titratable acidity, soluble tannin content and polyphenoloxidase activity were increasing. Combining organoleptic evaluation with color difference meter readings indicated that the quality inferiority of Tang-li juice was time-depended, the longer the storage time, the less the acceptability of color, flavor and taste. The chromatogram pattern of organic acid wasn't significant difference during storage period, however, the total organic acid content and citric acid were increasing. There was no significant changes in the content of malic acid, tartaric acid and ascorbic acid. The effect of temperature on juice color, flavor and taste was more significant than that of light during storage period. Adding 2% ascorbic acid could avoid browning efficiently. In Addition, using 0.5% carboxymethyl cellulose could also prevent precipitation of Tang-li juice during storage.