Repeated application of dynamic controlled atmospheres reduced superficial scald incidence in ‘Granny Smith’ apples

動態控制氣氛的重復應用減少了Granny Smith蘋果的表面燙傷發生率

Asanda Mditshwa ，Olaniyi Amos Fawole，Filicity Vries，Kobusvan der Merwe ，Elke Crouch，Umezuruike Linus Opar

A B S T R A C T
This study investigated the influence of repeated dynamic controlled atmosphere (DCA) application to control superficial scald of ‘Granny Smith’ apples. Fruit were stored for up to 16 w in DCA with a 14 d of interruption with regular air (RA) at −0.5 °C, 95% RH. Fruit was again stored in DCA. The scald potential for each storage time in each season was assessed by storing fruit in RA and used as the control, in order to ascertain the efficacy of repeated DCA treatments. Superficial scald incidence, total soluble solids (TSS), titratable acidity (TA), ground colour, fruit firmness and ethylene production were measured. Alpha-farnesene and 6-methyl-5-hepten-2-one (MHO) production were also measured using gas chromatography (GC–MS). Principal component analysis (PCA) was used to visualize metabolic changes and the relationship among them. Results showed maximum superficial scald incidence of 2% and 99% in repeated DCA and RA, respectively. Fruit stored in DCA repeatedly was characterized by a higher fruit firmness, ground colour and titratable acidity. Ethylene, α-farnesene and MHO production were significantly lower in repeated DCA compared to only RA stored fruit. Seasonal changes had no significant effect on metabolic parameters studied. The data distribution in the PCA displayed two clusters that could easily be identified. These clusters allowed distinction between fruit stored in RA only and repeated DCA. Ethylene, α-farnesene and MHO production had a strong and positive correlation with scald incidence. This study demonstrated that repeated DCA treatments can effectively control superficial scald.

研究了重復動態控制氣氛(DCA)對Granny Smith蘋果表面燙傷的控制作用。在-0.5°C，95%相對濕度下，將水果在DCA中儲存長達16 W，并中斷14 d的常規空氣(RA)。水果再次儲存在DCA中。為了確定DCA重復治療的有效性，通過在RA中貯藏水果并作為對照來評估每個季節貯藏時間的燙傷可能性。測定了表面燙傷發生率、總可溶性固形物(TSS)、可滴定酸度(TA)、底色、果實硬度和乙烯生成量。用氣相色譜法(GC-MS)測定了Alpha-farnesene 和6-甲基-5-庚烯-2-酮(MHO)的產量。采用主成分分析法(PCA)觀察代謝變化及其相互關系。結果表明，反復DCA和RA患者表淺性燙傷的發生率分別為2%和99%。在DCA中反復貯藏的果實具有硬度高、色澤淺、酸度可滴定等特點。在重復的DCA中，乙烯、α-farnesene和MHO的產量明顯低于僅儲存在RA中的水果。季節變化對所研究的代謝參數沒有顯著影響。PCA中的數據分布顯示了兩個易于識別的簇。這些集群允許區分存儲在RA中的水果和重復的DCA。乙烯、α-farnesene和MHO的產生與燙傷發生率有很強的正相關。本研究表明，反復DCA調控可有效控制淺表燙傷。