高壓處理技術對大目釋迦果泥理化性質的影響

大目釋迦（Annona squamosa L. cv. Da-Mo）為臺灣最主要的番荔枝經濟栽培品種，主要栽種於臺灣臺東地區，因其為典型的更年性水果，鮮果容易軟熟而不耐貯藏運輸，作為加工品又受限於熱處理後會產生苦味、特殊風味散失等負面效應。高壓處理（high pressure processing, HPP）是一種新興的非熱加工技術，以等壓方式作用在食品上，具破壞分子間的非共價鍵、改變酵素活性、促進成分萃取和抑制微生物生長等效果，並能保留較多的營養成分、維持天然色澤及延長食品的貯架壽命。本研究探討高壓處理技術中壓力與持壓時間對大目釋迦果泥物理特性、酵素活性和機能性成分的影響。在物理特性方面，黏度隨處理壓力上升而提高，粒徑則相對變小，熱處理亦有相同趨勢，而反覆高壓處理則無規律的變化；在酵素活性方面，多酚氧化酶、過氧化酶及聚半乳糖醛酸酶，均隨壓力上升而活性下降，果膠甲酯酶則以400 MPa持壓10分鐘酵素活性最低，而反覆高壓處理又較固定持壓在抑制酵素活性上有更顯著的降低，蔗糖轉化酶經高壓處理和熱處理後仍維持其活性，進而促進葡萄糖和果糖的轉化；在機能性成分方面，高壓處理可維持或提高總酚、類黃酮及維生素C含量。以較佳的反覆高壓處理條件進行基本成分及抗氧化活性測定，並在4℃進行三週貯藏試驗。結果顯示，反覆高壓處理及熱處理會使可溶性固形物和pH值略微下降，而可滴定酸則略微上升，果膠含量則顯著降低，葡萄糖、果糖及麥芽糖有上升的趨勢，熱處理顯著增加蔗糖含量；在抗氧化活性方面，均以反覆高壓處理後效果較熱處理顯著。經4℃三週貯藏後也可達微生物衛生標準，在色澤方面，反覆高壓處理能較對照組延緩色澤變化；在酵素活性方面，反覆高壓處理可降低多酚氧化酶及過氧化酶活性，但隨貯藏時間增長，僅熱處理能維持較低的酵素活性。綜合本試驗結果，反覆高壓處理能更有效的抑制酵素活性及保留或提高機能性成分，且具有抗氧化能力，可作為保存大目釋迦果泥的合適方法與加值應用性。

關鍵字

高壓處理；大目釋迦；理化性質；反覆加壓

並列摘要

Annona squamosa L. cv. Da-Mo is the most important economical cultivar of sugar apple in Taiwan and is mainly cultivated in Taitung, Taiwan. Sugar apple is a typical climacteric fruit that ripens and softens quickly during storage, and therefore is not durable for storage and transportation. In addition, it is rarely used in processed form due to its bitterness and loss of special flavor after heat treatment. High pressure processing (HPP) is a novel non-thermal processing technology. It involves applying equal pressure on food, breaking non-covalent bonds between molecules, affecting enzyme activity, promoting the extraction of components, and inhibiting microbial growth. Consequently, this process retains more nutrition, maintains natural color, and prolongs the shelf life of food. This study explores the effects of HPP on the physical properties, enzyme activities, and functional components of ‘Da-Mo’ sugar apple puree. The results of treatment effects on physical properties showed that viscosity was proportional to processing pressure, and the particle size became relatively small. Heat treatment showed the same trend, but repeated HPP showed irregular changes. Activities of polyphenol oxidase, peroxidase, and polygalacturonase decreased with increasing pressure. Pectin methylesterase showed the lowest activity at 400 MPa for 10 minutes, and repeated HPP decreased enzyme activities more than did fixed holding pressure. Sucrose invertase which promotes the conversion of glucose and fructose maintains its activity after HPP and heat treatment. The results of treatment on the functional components revealed that HPP can maintain or increase the content of total phenols, flavonoids and vitamin C. We therefore chose the better repeated HPP conditions to detect the basic ingredients and antioxidant activities of sugar apple puree. In addition, we also tested the effects of storing the puree processed at 4℃ for three weeks. The results showed that repeated HPP and heat treatment slightly decreased soluble solids and pH, while increasing titratable acid content slightly. For the basic content of the puree, the pectin level was significantly reduced, while glucose, fructose, and maltose contents increased. Heat treatment significantly increases sucrose content. The effect of repeated HPP was more significant on the antioxidant activity than that of heat treatment. After storage at 4℃ for three weeks, repeated HPP can also reach the microbiological hygiene standard. Repeated HPP could delay the color change compared with the control group. Repeated HPP reduced the activities of polyphenol oxidase and peroxidase, but as storage time increased, only heat treatment could suppress enzyme activity. Our results showed that repeated HPP is effective in inhibiting enzyme activity and retaining or improving the functional components of the puree. Moreover, repeated HPP also retained the antioxidant capacity of the puree. In conclusion, repeated HPP can be used as a suitable method and value-added applicability for preserving ‘Da-Mo’ sugar apple puree.