POLYGALACTURONASE AND PECTIN METHYLESTERASE ACTIVITIES OF CaCl₂ TREATED RED-FLESHED DRAGON FRUIT (<i>HYLOCEREUS POLYRHIZUS</i>) HARVESTED AT DIFFERENT MATURITY

Abstract

Fruits harvested at different maturity possess different biochemical constituents and physiological properties that make the fruits may react somewhat differently to the postharvest treatment. A study to examine the activity of Polygalacturonase (PG) and Pectin Methylesterase (PME) enzymes during storage in dragon fruit (Hylocereus polyrhizus) harvested at 28 days (Index 3) and 34 days (Index 5) after anthesis and postharvest treated with 0, 2.5, 5.0 and 7.5 g L −1 CaCl 2 was performed. The PG activity was lower in younger fruit and vice-versa for PME activity. Increasing concentration of CaCl 2 effectively reduced the activity of both enzymes. PG activity for fruit treated with 0, 5 and 7.5 g L −1 CaCl 2 increased linearly with the time of storage while its activity for the fruit treated with 2.5 g L −1 CaCl 2 was lower at the beginning of storage. PG activity of Index 5 fruits increased almost linearly during storage while its activity in Index 3 fruits was low at the early days of storage and later continued to increase until day seven. At both maturity indices, the PME activity was low at the early days of storage and later continued to increase until day seven. Overall, results obtained indicated that CaCl 2 postharvest treatment reduced both PME and PG activities thus slowing down the softening process giving an evident that calcium possess a distinguishable role in the reducing softening of fruit, regardless of maturity index.

Cell wall composition and enzyme-related activities in eggplant as affected by hot water, 1-MCP and calcium chloride treatments

“…On the other hand, postharvest CaCl 2 caused a significant decrease of PG (23-29%) and PME (25-28%) activities as compared to the respective controls in the Ber fruits (Jain et al, 2019). Moreover, PG activity was increased in dragon fruits treated with 0.5 and 7.5 g/L CaCl 2 , but PG activity was lower at the beginning of storage in fruits treated with 2.5 g/L (Awang et al, 2013). PME primarily catalyzes the demethylation of pectin, damaging the horizontal calcium bonds of the acidic polysaccharide chain, leading to cell division and providing a suitable substrate for PG (Brummell et al, 2004).…”

“…On the other hand, postharvest CaCl 2 caused a significant decrease of PG (23–29%) and PME (25–28%) activities as compared to the respective controls in the Ber fruits (Jain et al, 2019). Moreover, PG activity was increased in dragon fruits treated with 0.5 and 7.5 g/L CaCl 2 , but PG activity was lower at the beginning of storage in fruits treated with 2.5 g/L (Awang et al, 2013).…”

The effect of high‐pressure processing on reducing the glycaemic index of atemoya puree

“…As previously described by Awang et al ., 15 10 g AP was added to 20 mL buffer solution (pH 4.6) containing 0.1 mol L −1 sodium citrate, 1 mol L −1 NaCl, 13 mmol L −1 ethylenediaminetetraacetic acid, 10 mmol L −1 β‐mercaptoethanol and 2% (w/v) polyvinylpyrrolidone (PVP‐40), and the mixture was thoroughly vortexed at 430 × g for 30 min at 4 °C. After homogenization, the mixture was centrifuged at 24 148 × g for 30 min at 4 °C to obtain the supernatant as a crude enzyme extract.…”

Effects of 1-MCP and calcium chloride treatments on quality maintenance of full-ripe cherry tomatoes

“…Recently, CaCl 2 treatment has also been used to preserve horticultural crops and delay their softening, ripening, and deterioration, as well as for its role in sanitizing the food (Genanew, 2013). Calcium serves as a strong chelator in the linkage of cell wall constructions (Shiri et al, 2014), and as an inhibitor of cell wall degradation enzymes (Awang et al, 2013;Mansourbahmani et al, 2017). Moreover, calcium is an important mineral that influences the softness of fruit, its quality, post-harvest decay, and physiological disorders (Lurie, 2009).…”