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
The objective of this study was to evaluate the effect of pulsed electric fields (PEF) on the in vitro starch digestibility properties of oat flour. A wide range of PEF process intensity was investigated (electric field strength between 2.1 and 4.5 kV/cm and specific energy inputs between 52 and 438 kJ/kg using 20 μs square wave bipolar pulse at 100 Hz). The results revealed that PEF applied at a high electric field strength and energy 421 kJ/kg at any field strength intensities raised the RDS (from 15% to 19–20%), but the rate of starch digestion was not affected (maintained at 3.3–3.7 × 10−2 min−1 vs. untreated at 3.8 × 10−2 min−1). Further analysis of the structure, particle size, and thermal stability of PEF-treated oat flour through fractionation into three distinct flour segments revealed that PEF could cause major modifications in the particle size, damage and aggregation of starch granules, and destruction of the long- and short-range ordered structures of starch. Data gathered in this study indicate that PEF treatment can be a reliable strategy to modulate the in vitro starch digestibility of oat flour, either by reasonably slowing down the digestion rate or enabling a slightly higher amount of starch to be readily accessible by digestive enzymes without affecting the digestion rate.
1 August 2020 in Innovative Food Science & Emerging Technologies
This study aims to explore the opportunities offered by non-thermal food processing technologies, including high-pressure processing, pulsed electric fields, ultraviolet light, ultrasound, and microwave that could be viable for the agriculture commodities produced in the ASEAN region. The applications of these technologies across various food product categories (from dairy to fruits and vegetables, meat and seafood, beverages, condiments, fermented foods, edible oil, and ready-to-eat meals) focusing on microbial inactivation and mass transfer process enhancement, are systematically discussed to highlight their potential to foster the production of safe, nutritious, and fresh-like quality food products from the region. The adoption of non-thermal technologies can face several challenges that hinder the integration of these technologies in ASEAN, including high start-up costs, limited access to stable electricity and clean water, and inconsistencies in food regulations across countries. Information gaps related to the adoption of non-thermal technologies within the diverse food-related scenarios in ASEAN were identified and recommendations were given to improve the state of knowledge in the region. Overall, this work offers critical insights for policymakers, industry stakeholders, and researchers to consider inclusion of non-thermal technologies in food production as strategic approaches and tailored solutions to enhance the competitiveness of regional food products globally.