‘臺農二號’番木瓜果實氣調貯藏及氣變包裝貯藏之研究

Abstract

低氧濃度可延緩果實的呼吸作用及生理代謝，因此如何找出適合低氧濃度是氣調貯藏技術的核心要件。本研究評估不同氧濃度範圍對採收後番木瓜果實的生理反應及外觀表現等影響，期能有助於在採收後番木瓜果實氣調及氣變貯藏技術上。本試驗是以‘臺農二號’番木瓜果實15％黃熟度在25℃下以1％、3％、5％、8％、11％、14％、17％及20％與1％、3％、5％、8％、10％、11％及20％氧氣處理8天及再模擬櫥架8天，結果顯示，不同氧濃度處理下對果實呼吸率的反應可分成兩個生理反應區域，各分別為”危機區”（Crisis zone）其氧氣濃度低於3％及”恆定區”（Homeostatic zone）其氧氣濃度範圍於3~20％，再將”恆定區”分成兩部分，一為”彈性逆境區域”（Elastic stress zone）其氧氣濃度範圍在3~8％，另一為氧氣濃度範圍在8~20％。”危機區”與 ”恆定區”的區域劃分是依據3％O2濃度為有氧呼吸消失點。低於3％O2濃度，果實會產生有氧呼吸障礙並伴隨發生乙醇、果腔內異味及呼吸率提高，其乙烯生成雖受到抑制，但櫥架後果實轉色不均，外觀表現不佳，種子假種皮呈烏黑水浸狀。因此推論低於3％O2濃度時，果實進行無氧呼吸，大量累積乙醇後可能毒害細胞使果實接近生理瀕死狀態，此低於3％O2濃度範圍既稱為”危機區”。3％O2濃度以上至20％O2濃度則為果實行有氧呼吸，果實經不同氧濃度處理後，回到正常大氣下，果實仍能自我修復正常代謝，且無大量累積乙醇的現象發生；此3~20％O2濃度範圍內既稱為”恆定區”。再將”恆定區”分成兩部分，一為氧氣濃度高於8％至20％範圍，以10~20％O2濃度處理期間，果皮轉色正常及轉色速率趨勢相似，且呼吸率與乙烯釋放率仍能完全達到更年高峰；另一為3~8％O2濃度範圍，果實雖能正常代謝但因低氧濃度的影響使呼吸率降低、乙烯生成量受到抑制及果實轉色速率延緩；回到正常大氣下，果實自然後熟達完全轉黃天數約16天比較11~20％O2濃度處理果實能延緩果實轉色約5~6天，此3~8％O2濃度範圍內既稱為”彈性逆境區”；再從”彈性逆境區”中選擇適當的低氧濃度條件，則以模擬25℃櫥架8天後評估果實品質，以5％O2濃度處理為較佳，外觀表現良好，果皮色澤呈亮黃色，全可溶性固形物為11 0Brix + 0.2，硬度在14 N + 1.9，果腔內無異味發生，腐爛率低於3％。另以葉綠素螢光儀檢測番木瓜果實之螢光比值（Fv/Fm）與果肉乙醇含量呈負相關性（r = -0.96, P＜0.0001）。因此建議‘臺農二號’番木瓜果實以低氧貯藏環境不低於3％O2濃度，低氧5％O2濃度可做為氣調貯藏技術之參考。

The low oxygen concentration may retard the respiration and physiological metabolism of the fruit. Therefore, how to find suits the low oxygen concentration is important core of the controlled atmosphere. This study in different oxygen concentration are impeacted on physiological reaction and appearance performance of papaya fruit, it could be help controlled atmosphere storage and modified atmosphere package in the technology. This experiment is by `Tainung No. 2' papaya fruit of 15% yellowing which was treated with flow-through system, 1%, 3%, 5%, 8%, 11%, 14%, 17% and 20% of oxygen, and 1%, 3%, 5%, 8%, 10%, 11% and 20% of oxygen treatment during 8 days and than simulates 8 days of shelf-life at 25℃, the result showed that separable becomes two physiological reaction region to the respiration rate response of the different oxygen concentration, each respectively is the ”Crisis zone” its oxygen level is lower than 3%O2 and” Homeostatic zone” its oxygen level in 3~20%O2, and then ”Homeostatic zone” will divide into two part, one is ”Elastic stress zone” its oxygen level in 3~8%O2, another one is the oxygen level in 8~20%O2. ”Crisis zone” and ”Homeostatic zone” the region division is rests on the 3%O2 level for the extinction point. Is lower than the 3%O2 level, the fruit can produce the aerobic respiration barrier and follow has in the ethanol, the fruit cavity produce unusual smell and the respiration rate enhances, although its ethylene production comes under the suppression, but fruit is uneven during shelf life, the appearance performance is not good, the seed arillus assumes the pitch-black water soaked occurred. it is suggest lower than the 3%O2 level, the fruit carries on the anaerobic respiration, it possibly to poison the cell to cause the fruit close to be death condition after accumulates the ethanol, this is lower than the 3%O2 level to be called ”Crisis zone”. Above the 3%~20%O2 level is aerobic respiration for the fruit, the fruit returns to under the normal atmosphere after different oxygen concentration processing, the fruit still could repair and normal metabolism, also the not accumulation ethanol. In this 3~20%O2 level already is called” Homeostatic zone”. The ”Homeostatic zone” will divide into two parts, one will be higher than 8% O2 for the oxygen level to 20%O2, by 10~20%O2 level processing period, the peel ripening normal and the ripening tendency will be similar, also the respiration rate and the ethylene production still could achieve the climacteric peak completely. another one is the 3~8%O2 level, the fruit can be the normal metabolism, but the low oxygen concentration cause respiration rate to reduce, ethylene production comes under the suppression and the fruit ripening postponement. when returns to normal atmosphere, the fruit ripening reaches 100％ yellowing is number of days 16 days to compare the 11~20%O2 level processing fruit completely to be able approximately to delay the fruit ripen approximately 5~6 days, in this 3~8%O2 level already is called “Elastic stress zone”. Again chooses the optimal low oxygen concentration condition from “Elastic stress zone”, and then evaluation fruit quality after simulates shelf life of fruit to put up 8 day at 25℃. it takes 5%O2 level as good, the appearance is good, the peel luster assumes the light yellow, the total soluble solids is 11 0Brix + 0.2, firmness in 14 N + 1.9, no development of off-odor occurrence in the fruit cavity , the decay rate is lower than 3%O2. By the chlorophyll fluorescence observance of ceremony measured in fluorescence of ratio (Fv/Fm) assumes the negative correlation with the fruit pulp ethanol content (r = -0.96, P< 0.0001). Therefore suggested `Tainung No.2' papaya fruit stores the environment by the low oxygen not to be lower than the 3%O2 level, the low oxygen 5%O2 level may do reference for the controlled atmosphere storage technology.