A typical symptom of postharvest chilling injury (PCI) in pineapple fruit (Ananas comosus (L.) Merr.) is internal browning (IB) near the fruit core. Since vascular bundles (VBs) are localized to this region, it was hypothesized that the VBs might be the site of IB. To test this, the anatomy and histochemistry of VBs during chilling stress in four pineapple cultivars with different levels of sensitivity to PCI were examined. Fruit were stored at 10°C for up to three weeks to stimulate translucency symptoms (TS; the initiation of IB). After three weeks of chilling exposure, the cultivars 'MD2' showed 0%, 'Pattavia' and 'Savee' showed 10-16%, and 'Trad Sri Thong' showed 100% TS and IB symptom. Scanning electron microscopy and in situ histochemical staining techniques that detect enzymes and substrates commonly associated with IB initiation were used in parallel. The TS of pineapple fruit coincided with the collapse of the phloem tissue. The VBs in the tissue where IB was initiated (i.e., the flesh adjacent to the core or F/C) had the highest activity of polyphenol oxidase, hydrogen peroxide, and phenolic compounds. The IB-resistant 'MD2' genotype had fewer VBs, but a greater proportion of sclerenchyma fibers (P<0.05) than did the susceptible 'Trad Sri Thong'. Based on these data, the first report of pineapple IB occurrence in the phloem was proposed.

Makapuno is a high-value commercial coconut with distinct sensory attributes, however the postharvest conditions required to maintain quality are unknown. To address this, partially de-husked mature Makapuno coconut fruit were stored at 2, 5 or 30°C and were then evaluated after transferring to 30°C for 3 days to simulate conditions in retail markets. During storage at 30°C, the fruit showed a moderate respiration rate of 40-60mgCO2kg-1h-1, a low ethylene production rate of 0.6-0.8μLC2H4kg-1h-1 and storage life was 3 days. In contrast, storage at 2°C or 5°C markedly reduced respiration rates to 4 and 20mgCO2kg-1h-1, respectively, and storage-life increased dramatically from 3 days to 6 weeks. Generally, cold storage delayed fruit deterioration by limiting weight loss, kernel browning and malondialdehyde content, however, after the fruits were transferred to 30°C, those previously held at 2°C showed signs of chilling injury, while those held at 5°C did not. Modified atmosphere packaging (MAP) using high oxygen transmission rate (OTR) bags in combination with 5°C storage extended fruit storage-life 20-fold, from 3 days at ambient conditions to 10 weeks. The combination of MAP and 5°C storage reduced weight loss (4-fold), the incidence of surface mold and the quality parameters measured were comparable to values in freshly harvested fruit. © 2014 Elsevier B.V.