Impact of drying on the bioactive compounds and antioxidant properties of bignay [Antidesma bunius (L.) Spreng.] pomace

Abstract

Bignay pomace is a processing byproduct that can be a source of bioactive compounds. However, a suitable dehydration method should be considered to efficiently valorize this waste material into high-value food ingredient and maximize its health-promoting properties. Bignay pomace was subjected to convection oven-drying and freeze-drying to investigate the effect of these pre-processing techniques on the physicochemical, bioactives, and antioxidant properties of the samples. Both drying methods significantly (p<0.05) changed the total phenolic and anthocyanin contents of bignay pomace while flavonoids and tannins were not significantly affected. Freeze-drying of samples resulted in higher phenolic content (1742 vs. 1273 mg gallic acid equivalent/100 g DW) and anthocyanin content (496 vs. 223 mg cyanidin-3-glucoside equivalent/100 g DW) than convection oven-drying. Freeze-drying also resulted in higher antioxidant properties based on DPPH, ABTS radical scavenging activity, and FRAP assays. Bignay pomace extract was analyzed through HPLC (with photo-diode array detector) for its phenolic profile and nine compounds were identified, with catechin and epicatechin as the dominant components. HPLC analysis also showed that while the drying process does not influence the phenolic profile of the samples, it significantly affected the concentration of phenolic compounds present. The results of this study showed that freeze-drying is a more viable method to retain the majority of bignay pomace’s functional properties compared to convection oven-drying. Graphical Abstract

Colour, nutritional composition and antioxidant properties of dehydrated carrot (Daucus carota var. sativus) using solar drying techniques and pretreatments

“…Glycosides exhibit greater reducibility in comparison to phenols and flavonoids, and are more prone to the effects of temperature and oxygen concentration. Phenols and flavonoids exhibit lesser reducibility in comparison to glycosides, resulting in their decreased susceptibility to temperature and oxygen concentration [ 48 ]. However, our finding was in contrast to evidence of [ 49 , 50 ] where they reported a decrease of TPC with the increase in temperature (70–80 °C) and drying durations.…”

“…In addition, it can be elucidated that certain flavonoids are formed as oxidation products of phenols under high temperature conditions. As a result, there is a phenomenon where the number of flavonoids retained is higher at high temperatures than at low temperatures [ 48 ].…”

Village-level Processing of Pangi (Pangium edule Reinw.) Seeds by the Obu Manuvu Improves the Edibility and Level of Some Nutritional Factors [RESEARCH NOTE]

“…However, a modification (heating at 60°C for 1 h) during extraction has been incorporated in the standard FC method for the purpose of degrading the other phenolic compounds while retaining the tannins. In the study of Zubia et al (2023), the total phenolic content of bignay pomace significantly decreased when the sample was dried at 45°C for 48 h; however, tannin content was not affected. Further, in the study of Setyaningsih et al (2016), it was established that 36 out of 40 phenolic compounds (tannin not included in the study) were stable up to 50°C only.…”

“…The tannin content of Pangi seeds was analyzed using the modified Folin-Ciocalteu method based on the procedures of Chye and Sim (2009) and Mohammed and Manan (2015). The sample was prepared by dissolving 1 g in 25 mL of 80% aqueous methanol (Scharlau, Spain) followed by heating in a water bath at 60°C for 1 h. The heating step at elevated temperature for 1 h aimed to degrade the phenolics except the tannins (Setyaningsih et al 2016;Das et al 2020;Zubia et al 2023). The homogenate was centrifuged (NovaFuge B115-20R, Senova, China) at 7000 rpm for 5 min at 4°C.…”

Characterization and storage stability of microencapsulated black jamun (Syzygium cumini) pulp extract via freeze drying

“…Freeze-drying produces more appealing dried products that have higher retention of nutrients, color, and flavor property (Zubia et al, 2023). This process increases the rehydration rate and reduces the microbial effects that produce a better quality product (Ratti, 2001).…”