Search

Frozen storage was introduced to maintain the quality and prolong the shelf life of durian pulps. The aim of the present work was to evaluate the changes of organic acids, sugars, and volatile organic compounds (VOCs) in "Musang King" ("MK") and "D24" pulps under long‐term frozen storage. Organic acids in "MK" and "D24" only showed slight decrements, but sugar contents especially sucrose drastically decreased during 1 year frozen storage. Fructose and glucose in both durian pulps increased during the first half period of storage; this might be due to the conversion of sucrose to monosaccharides during storage. Freezing also caused the loss of some VOCs especially sulfur‐ and ester‐containing VOCs in "MK" and "D24" pulps. These results indicated that the flavor losses in "MK" and "D24" were mostly related to the losses of ester‐containing compounds rather than organic acids and sugar compositions following 1 year frozen storage. Practical applications: Freezing practice has been successfully used to export Malaysian durians to other countries for the past few years and the frozen durian it is expected to boost up the economy of Malaysia. Blast freezing is capable to extend the shelf life of the pulp of durian and provide a continuous supply throughout all year round as durian is a seasonal fruit. Even though the frozen pulp is still edible up to 1 year storage, some qualities of such as flavor are affected during frozen storage. [ABSTRACT FROM AUTHOR]

• Acetone-phenol was the optimal method to extract proteins from durian pulp. • Expression of 18 proteins were affected in durian pulps after frozen storage. • 15 proteins were down-regulated and three proteins were up-regulated. • Down-regulation of proteins mainly related to cellular components and transport. Four different methods were evaluated to extract proteins from "Musang King" durian pulps and subsequently proteins with different abundance between fresh and long term frozen storage were identified using two-dimensional polyacrylamide gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analyses. The acetone-phenol method was found to produce good protein yields and gave the highest gel resolution and reproducibility. Differential protein analyses of the durian pulp revealed that 15 proteins were down-regulated and three other proteins were up-regulated after a year of frozen storage. Isoflavone reductase-like protein, S-adenosyl methionine synthase, and cysteine synthase isoform were up-regulated during frozen storage. The down-regulation of proteins in frozen durian pulps indicated that frozen storage has affected proteins in many ways, especially in their functions related to carbohydrate and energy metabolisms, cellular components, and transport processes. This study will enable future detailed investigations of proteins associated with quality attributes of durians to be studied. [ABSTRACT FROM AUTHOR]

• Musang King and D24 are the most demanded durians among other clones in Malaysia. • β-carotene in pulp and paste decreased ≥ 20 % in durian after 12 months frozen storage. • Frozen storage minimized microbial contaminations and prolonged the shelf life of durians. • Durian paste is more prone to microbial contaminations as compared to pulp. Exposing fruits to freezing temperature has been shown to successfully extend the shelf life and control the microbiological activity in the fruits. However, freezing could also lead to undesirable losses in the fruit quality. The present work was conducted to investigate the effect of frozen storage on physicochemical qualities and microbial contaminations of "MK" (Musang King) and "D24" durian pulp and paste for one year. During frozen storage, both durian pulp and paste lost 1 %–2 % of their weight along with an increase in pulp softening. Changes in color intensity during freezing storage shifted the golden yellow "MK" pulp to higher hº (lighter yellow) and this directly reduced the total carotenoids and ß-carotene contents in "MK". Similarly, "D24" changed to pale yellow alongside reduction on L * and C* after one year frozen storage. Long term frozen storage in the present work also decreased the SSC and ascorbic acid contents for both durian pulp and paste. However, the pH and TA were not affected. "MK" and "D24" pulp showed lower microbial contamination than paste, with higher contaminations were observed in "D24". These results showed that frozen storage could be used to preserve the quality of durians for less than one year of storage. [ABSTRACT FROM AUTHOR]

• Yellow color of durian pulp often due to the presence of ß-carotene. • Sulfur- and ester-containing compounds are major VOCs in durian. • Five VOCs identified as fingerprints for durian during ripening. • Multivariate analysis was used to differentiate the VOCs in different clones. The aim of the present work was to characterize the quality of durians at consumptions stage. Seven clones of durian namely "Musang King", "D24″, "D88″, "IOI", "XO", "Red Prawn" and "Black Thorn" were characterized based on their physiochemical properties. The organic acid contents, sugar compositions and β-carotene of durian clones were measured by high-performance liquid chromatographic (HPLC), while the volatile organic compounds (VOCs) were analyzed using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC MS). There were significant differences on all the postharvest parameters in the selected durian clones. "Black Thorn" having orange pulp yieled the highest β-carotene content (4.55 × 10−5 kg/kg FW). The dominant sugars in the pulp of all durian clones were dominated by sucrose followed by glucose and fructose. Sulfur- and ester-containing compounds were the predominant VOCs found. Principal component analysis (PCA) allowed for the grouping of different durian clones based on VOCs. [ABSTRACT FROM AUTHOR]