高壓處理對熱敏性果汁機能性成分及品質變化之影響

Effect of High Pressure Processing on Functional Ingredient and Quality of Heat-sensitive Juice

楊蕙安(Huei-An Yang)

指導教授 ： 吳思節

國立臺灣大學/生物資源暨農學院/園藝暨景觀學系/碩士(2016年)

https://doi.org/10.6342/NTU201603401

摘要

檸檬果汁及蘋果果汁為國人喜愛飲品之一，但經傳統熱加工處理後，會破壞其營養成分及影響外觀品質，進而降低消費者購買意願。多酚氧化酶、過氧化酶及果膠甲酯酶會造成果汁褐變及混濁，為影響蘋果果汁外觀品質之關鍵酵素。
本研究希望藉由高壓處理技術達到破壞酵素及維持營養成分的目的，首先將檸檬果汁及蘋果果汁分為三大組，控制組(Control)、傳統熱處理(Thermal processing，TP；65°C，30分鐘)及三個不同高壓處理(High pressure processing，HPP)條件200 Mpa (10、20、30分鐘)、300 MPa (10、20、30分鐘)、400 MPa (5、10、20分鐘)。不同加工處理對檸檬果汁及蘋果果汁pH、可溶性固形物及可滴定酸並無顯著影響，而總生菌數雖無法像傳統熱殺菌完全殺滅，但以100 MPa處理10分鐘兩者皆可達安全衛生標準。隨著處理壓力及時間增加，總生菌數也有降低的趨勢，大腸桿菌群則是未檢出，呈陰性。影響蘋果果汁、檸檬果汁外觀品質的關鍵酵素多酚氧化酶及過氧化酶並無顯著降低的效果，但蘋果果汁的果膠甲酯酶於300 MPa處理10及20分鐘後活性隨之下降0.17 ± 0.012 ~0.19 ± 0.026 [ΔOD min-1 (g of fw)] ，在400 MPa則是處理20分鐘後隨之下降，由此可知高壓處理300 MPa短時間對蘋果果汁果膠甲酯活性具有抑制效果，但檸檬果汁則無顯著差異。而營養成分部分檸檬果汁經300 MPa處理10分鐘條件下可維持和控制組相當的維生素C含量(211.9 mg / L)，蘋果果汁經200 MPa處理10分鐘條件下可維持和控制組相當的維生素C含量(145.9 mg / L)。影響果汁濁度的可溶性蛋白變化，在檸檬果汁中以300 MPa處理30分鐘會降至最低，蘋果果汁則是以200、400 MPa以及較長的處理時間會隨之下降。熱敏性蘋果果汁利用高壓處理可達到和傳統熱處理相同的殺菌效果，且在維持其營養價值及外觀品質上效果皆比傳統熱加工良好。
另外，選出最佳高壓條件200 MPa、300 MPa、400 MPa、600 MPa處理20分鐘，並以加熱組及控制組作為比較，進行蘋果果汁4°C儲架試驗兩週。結果顯示，利用加熱及壓力處理300 MPa以上可達殺菌效果，經儲架試驗其pH、可溶性固形物、可滴定酸皆無顯著改變，說明不同殺菌處理對蘋果果汁物理性質影響不大，然而營養成分隨儲藏時間增加而下降，但利用高壓處理皆能達到比控制組及加熱組較佳的保留效果。最後，酵素活性部分多酚氧化酶各處理間無顯著差異，過氧化酶活性以200 MPa處理具有下降趨勢，果膠甲酯酶則是有提升的現象。
綜合以上結果，檸檬果汁及蘋果果汁以高壓處理100 MPa以上，儲架試驗則以300 MPa以上可達到殺菌效果。而高壓處理除了不影響果汁物理成分，相較於加熱處理也可得到較好保留果汁中營養成分的效果。

關鍵字

檸檬果汁 ； 蘋果果汁 ； 多酚氧化酶 ； 過氧化酶 ； 果膠甲酯酶

並列摘要

Lemon juice and apple juice are popular beverages in Taiwan, but after conventional heat processing, it will destroy its nutrients and affect the appearance and quality that reduce consumer willingness to buy. Polyphenol oxidase (PPO), peroxidase (POD) and Pectin methyl esterase (PME) can cause browning of fruit juices and turbid apple juice as affecting the appearance quality of the key enzymes. PPO、POD and PME are key enzymes, which can cause fruit juices to be browning and reduce its appearance quality or make it cloudy.
In this study, we utilize the high-pressure processing technique to destroy the enzymes activity and maintain the nutrients. First, the lemon juice and apple juice are divided into three groups: untreated (Control), traditional heat treatment (Thermal processing, TP ; 65°C /30 min), and high pressure processing (HPP) with three conditions: 200 MPa (10、20、30min)、300 MPa (10、20、30min)、400 MPa (5、10、20 min). Furthermore, the lemon juice and the apple juice have no significant change on TP and HPP. Although the total microorganisms may not be completely sterilized like a conventional heat sterilization; however, both juices can reach the safety standard with 100 MPa for 10 minutes processing. Associated with the increase of the total processing time and pressure plate count decreases, and Escherichia coli coliform is not detected; i.e., negative.
PPO and POD, the key enzymes effecting appearance quality of lemon and apple juices, do not significantly decrease. PME activity in apple juice reduces at 300 MPa 10 and 20 minutes treatment，0.17 ± 0.012 ~0.19 ± 0.026 [ΔOD min-1 (g of fw)] in 400 MPa PME activity reduce at 20 minutes treatment and from the results we can know that in 300 MPa short time treatment can reduce PME activity in apple juice, however no significant influence on lemon juice. That is to say, the high-pressure treatment has effect on apple juice’s PME active destruction to some extent.
For nutrients, the lemon juice can reach the equival vitamin C 211.9 mg / L content, the same to the control group with the 300 MPa for 10 minutes treatment, and apple juice can reach the equival vitamin C 145.9 mg / L content, the same to the control group 200 MPa for 10 minutes treatment. On the other hand, as for soluble proteins affecting turbidity, that in lemon juice reduces to a minimum at 300 MPa for 30 minutes treatment and that in apple juice reduces when treated with 200, 400 MPa pressure treatment and longer time. The heat-sensitive apple juice with high-pressure treatment can achieve the same sterilization effect to conventional heat treatment, and is better than the traditional thermal processing in maintaining the nutritional value and appearance quality.
Besides, after the apple juices are treated with the optimum conditions of 200, 300, 400, and 600 MPa for 20 minutes, it was stored at 4°C in two weeks. The results show that the thermal processing and pressure treatment for 300 MPa or higher has sterilization effect. In addition, the pH, soluble solids, titratable acidity after storage do not have significant changes, meaning that different processing does not change the physical properties; however, nutrients decreases with increasing storage time. The use of high-pressure treatment offers better retention effect when compared with the control group the heating group. Finally, it also shows that enzyme content of PPO has no significant differences among the treatments, but content of POD enzymeaa with 200 MPa treatment declines, PME increased at 300 MPa.
Based on the above results, lemon juice and apple juice can achieve sterilization effect with 100 MPa or higher treatment, but 300 MPa or higher pressure for storage. The high-pressure treatment not only does not affect the physical ingredient juice, but also reserves better nutrients compared to the heat treatment.

並列關鍵字

lemon juice ； apple juice ； polyphenol oxidase ； peroxidase ； pectin methyl esterase

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