Carotenoids in durian fruit pulp during growth and postharvest ripening

Impacts of Thermal Processing, High Pressure, and CO2-Assisted High Pressure on Quality Characteristics and Shelf Life of Durian Fruit Puree

Durian fruit puree (DFP) is a nutrient-dense food, but it has a short shelf life. Presently, little research has been undertaken on extending the shelf life of DFP. Hence, it is necessary to develop treatment methods that can prolong the shelf life of DFP. In the present study, thermal processing (TP), high-pressure processing (HPP), and CO₂-assisted HPP (CO₂ + HPP) treatments are used for DFP, and their influences on quality properties of DFP during storage (35 days, 4 °C) are investigated. Compared to other treatments, the CO₂ + HPP treatment had a lower pressure and a shorter time to achieve the same effect of inactivating the microorganisms of DFP. During storage, CO₂ + HPP treated DFP showed higher retention rates of sugars, total soluble solids, color, bioactive components, and antioxidant capacity in comparison with other treated DFPs. Moreover, after 35 days of storage, the microbial count of (CO₂ + HPP)-treated DFP (3.80 × 10³ CFU/g) was much lower than those of TP (4.77 × 10⁵ CFU/g) and HPP (8.53 × 10³ CFU/g)-treated DFPs. The results of this study reveal that CO₂ + HPP treatment could not only better preserve the quality of DFP, but also effectively extend the shelf life of DFP, providing an effective method for the processing of DFP.

Investigation of key chemical species from durian peduncles and their correlations with durian maturity

The popularity and high price of durian make quality control in terms of ripeness very important, which in turn depends heavily on harvesting at an appropriate maturity stage. To date, reports on data-driven methods for maturity prediction are scarce, with many rather focusing on ripeness prediction. Herein, we report the first disclosure of key molecular markers in the liquid extract of durian peduncle that can be a predictive tool for maturity. Multiple chromatographic and spectroscopic techniques including TLC, HPLC, PS-MS, LC-MS/MS, and NMR, were used to characterize chemical profiles of the aqueous extracts from peduncles at different ages. Four compounds that show positive correlations with maturity were identified as sucrose, asparagine, arginine, and pipecolic acid, with asparagine as the most abundant species. This finding paves the way for more research of high impact such as the relationship between biochemical reactions in peduncle and pulp, and the development of accurate and non-destructive sensors for maturity prediction.

Metagenomic-based Approach for the Analysis of Yeast Diversity Associated with Amylase Production in Lai (Durio kutejensis)

This study reported the application of a next generation sequencing (NGS) analysis of yeast diversity in native Indonesian fruit, Durio kutejensis, collected from Borneo, Central Kalimantan. The analysis was designed to observe the microbial consortium associated with solid state fermentation (SSF) for amylase production. Together with the additional data from culture-dependent analysis, we observed the morphological features, molecular characteristics, and amylase concentration produced by each isolate. We performed Solid State Fermentation (SSF) for amylase production and the enzyme activity was then determined using UV-Vis spectrophotometer at 540 nm. Result obtained from metagenomic approach consist of 4 group that fungal species included in the Ascomycota identified as Botryosphaeria dothidea (1.35%), Lasiodiplodia crassispora (17.62%), Aureobasidium pullulans (55.02%), Paraphoma chrysanthemicola (11.38%), Preussia funiculate (1.90%), Sporormiella intermedia (0.82%), Myrothecium gramineum (1.35%), Fusarium oxysporum (6.24%), Fusarium proliferatum (3.25%) and Phialemoniopsis curvata (1.08%). The results of isolation using culturable medium in the form of YMA obtained 40 yeast isolates. A total of 40 representative isolates from durian fruit were screened, two positive amylase isolates based on clear zones formed were DU 4.2 (Candida sorboxylosa) and DU4.22 (Cyberlindnera fabianii) isolates with amylolytic index of DU 4.2 isolates at 0.24 and DU 4.22 at 0.72 with an incubation time of 48 h. The highest amylase enzyme activity was found in isolate DU 4.2 of 31.21 U / mL.

Bioactive Compounds, Nutritional Value, and Potential Health Benefits of Indigenous Durian (Durio Zibethinus Murr.): A Review

Durian (Durio zibethinus Murr.) is an energy-dense seasonal tropical fruit grown in Southeast Asia. It is one of the most expensive fruits in the region. It has a creamy texture and a sweet-bitter taste. The unique durian flavour is attributable to the presence of fat, sugar, and volatile compounds such as esters and sulphur-containing compounds such as thioacetals, thioesters, and thiolanes, as well as alcohols. This review shows that durian is also rich in flavonoids (i.e., flavanols, anthocyanins), ascorbic acid, and carotenoids. However, limited studies exist regarding the variation in bioactive and volatile components of different durian varieties from Malaysia, Thailand, and Indonesia. Experimental animal models have shown that durian beneficially reduces blood glucose and cholesterol levels. Durian extract possesses anti-proliferative and probiotics effects in in vitro models. These effects warrant further investigation in human interventional studies for the development of functional food.

Carotenoid accumulation in durian (Durio zibethinus) fruit is affected by ethylene via modulation of carotenoid pathway gene expression

Carotenoid content in durian (Durio zibethinus) fruit is an important aspect of fruit quality, with different cultivars distinguished by differing pigmentation. We have studied the dependence of carotenogenesis on ethylene. Fruit of the cultivar 'Chanee' harvested at the mature stage were either left untreated (controls), treated with 1-methylcyclopropene (1-MCP) for 12 h, or treated with application of an aqueous ethephon solution to the stem end, or treated for 12 h with 1-MCP followed by ethephon application. Fruit were then stored for 9 d at 25 °C. Pulp color of durian became steadily yellowish as a result of accumulation of carotenoids, which were mainly beta-carotene, and alpha-carotene, with a minor amount of zeaxanthin and lutein. 1-MCP delayed the increase in the accumulation of beta-carotene, alpha-carotene, and zeaxanthin, but not lutein. In contrast, ethephon had no significant effect on carotenoid accumulation. The expression of zeta-carotene desaturase (ZDS), lycopene beta-cyclase (LCYB), chromoplast specific lycopene beta-cyclase (CYCB) and beta-carotene hydroxylase (BCH) genes was highly correlated with carotenoid content and pulp color.1-MCP resulted in significant down-regulation of ZDS, LCYB, CYCB and BCH expression. The accumulation of beta-carotene and alpha-carotene appears to be controlled by the level of expression of LCYB gene, whose function was tested in bacteria to show conversion of lycopene and delta-carotene to beta-carotene and alpha-carotene, respectively. These results suggest that ripening-induced carotenoid accumulation is regulated by endogenous ethylene controlling the expression of key genes such as LCYB.