‘珍珠拔’番石榴貯運氣變包裝技術之研究

Abstract

番石榴( Psidium guajava L.)屬於寒害敏感型熱帶水果，全年生產但品質不一，利用長程低溫貯運易發生寒害，嚴重阻礙行銷國際市場。本試驗目的在開發 ’珍珠拔’ 番石榴氣變包裝條件。利用兩果一袋之小包裝測試不同季節生產的’珍珠拔’冷藏後寒害表現的差異性，使用主動氣變包裝及減壓包裝處理組貯藏期可延長至28天以上。以不同厚度之LDPE袋進行10公斤外銷箱包裝測試，由於厚度太高會導致袋內二氧化碳累積太高，而包材過薄則會使袋內氧氣太高、二氧化碳太低，因此經過包材及氣體篩選，找出最適厚度之LDPE袋搭配主動氣變包裝對’珍珠拔’春、夏、秋季果實品質有最好維持效果。 進行貯運模擬試驗，外銷果品模擬新加坡、東南亞、加拿大市場，而內銷果品則模擬加拿大市場，比較七分熟與九分熟兩不同成熟度之貯運效果，可看到模擬貯運至三週，以七分熟之主動氣變處理有最低寒害指數0.7級，其次為減壓處理(V10)，七分熟對照組與九分熟氣變處理組有相同寒害指數1.6級，最高寒害為九分熟對照組之3.2級；果腐率也呈現相同現象，兩成熟度氣變處理組皆能有效降低果腐維持品質。觀察夏季果實模擬貯運新加坡(14天)或外銷船運至加拿大溫哥華（28天）及多倫多(35天)市場，對到貨品質與20℃回溫3天果實販售櫥架期品質之影響。秋季果實比較高雄’燕巢’果實使用氣變包裝之效果。番石榴以5℃冷藏貨櫃海運25天抵達加拿大溫哥華市場，結果與之前實驗室模擬試驗結果一致，氣變包裝效果與減壓包裝到貨可售率差異不顯著，皆明顯優於現行包裝對照組；經回溫展售3天，氣變包裝組在可售率與風味品質呈現最佳保鮮效果，而減壓包裝劣變速度則較快。 氣變包裝對於九分熟採收成熟度（內銷成熟度）、風味佳的果實，也呈現較佳的保鮮效益，未來可藉由此技術，提高外銷番石榴果實採收成熟度，以改善目前外銷‘珍珠拔’風味不佳的瓶頸問題。另外，本計畫所開發的氣變包裝技術，可以融入現行番石榴外銷包裝場作業流程，具有推廣應用的潛力，特別是在夏季及秋季。試驗開發之氣體模型，可用來預估國產外銷番石榴之櫥架壽命，根據此模式若擴大可應用至不同園產品，也可能使用不同貯運溫度或包材去進行測試。

Guava (Psidium guajava L.) is a chilling sensitive tropical fruit. It can be produced whole year, and the quality is unstable. The fact that long-term cold transportation and cold treatment usually render severe chilling injury (CI) impedes exporting for international markets. The purpose of this research is to investigate the effect of atmosphere modification technology on cold treatment of ‘Jen-Ju bar’ guava fruit. Test the different reaction to chilling injury after storage of ‘Jen-Ju bar’ guava fruit quality with two fruit per packaging in four different seasons. Using active modified atmosphere packaging (MAP) and lower pressure packaging (V10) can prolong the storage period to 28 days. Bulk packaging (10 kg/box) to test the suitable low density polyethylene (LDPE) film with four different thickness for ‘Jen-Ju bar’ guava fruit with export maturity (70% ripe). The effect of the thicker film will cause the high accumulation of CO2 concentration, and thinner film will cause the O2 concentration too high and CO2 concentration too low. The suitable LDPE film with active MAP has the best effect to maintain the quality in all seasons. To know the storage ability in two maturities, simulating transport the export maturity to Singapore, Southeast Asia, and Canada, and domestic maturity to Canada. Export maturity with active MAP has the lowest CI index 0.7 grade, and the lower one is V10. The control treatment in export and domestic maturity with active MAP has the same grade (1.6), and the control treatment in domestic maturity has the highest CI index (3.2 grade). The fruit decay has the same trend, and the MAP treatment in two maturities both can lower the decay and maintain the fruit quality. Observe the effect of simulation experiment to Singapore (for 14 days) or shipping transportation to Vancouver, Canada (for 28 days) on fruit quality investigate of arrival and the shelf life (followed by 3 days at 20˚C) in summer season. Check the storage ability with active MAP of guava fruits from ‘Yan-chao’, Kaohsiung in fall season. Guava fruit with active MAP of marine container transportation at 5℃ to Vancouver, Canada by 25 days, has the same trend of previous test simulation in laboratory. The salability of arrival has no significant different between MAP and V10 treatment, and significant prior from control treatment. After the 3 days shelf life, MAP treatment can maintain the best quality on salability and flavor, but V10 treatment loss its quality rapidly. MAP to the domestic maturity which has better flavor, can also have the better fresh-keeping benefits. In the future, this technique can be using to export the higher maturity that have better flavor to solve the essential problem of less flavor to guava of lower maturity for export. The MAP technique have good benefit and potential for commercial application, especially in summer and autumn. The MAP gas modeling development in this thesis can be predicted the storage life of export-maturity guava fruit, and it may use on different material or temperature.