This study aims to determine the influence of (1) ultrasound-assisted extraction (UAE), (2) microwave-assisted extraction (MAE) and (3) a combination of ultrasound–microwave-assisted extraction (UMAE) on the yields of fucose-sulphated polysaccharides (FSPs), total soluble carbohydrates and antioxidants extracted from A. nodosum. Scanning electron microscopy (SEM) was used to evaluate the influence of the extraction technologies on the surface of macroalgae while principal component analysis was used to assess the influence of the extraction forces on the yields of compounds. UMAE generated higher yields of compounds compared to UAE and MAE methods separately. The maximum yields of compounds achieved using UMAE were: FSPs (3533.75 ± 55.81 mg fucose/100 g dried macroalgae (dm)), total soluble carbohydrates (10408.72 ± 229.11 mg glucose equivalents/100 g dm) and phenolic compounds (2605.89 ± 192.97 mg gallic acid equivalents/100 g dm). The antioxidant properties of the extracts showed no clear trend or extreme improvements by using UAE, MAE or UMAE. The macroalgal cells were strongly altered by the application of MAE and UMAE, as revealed by the SEM images. Further research will be needed to understand the combined effect of sono-generated and microwave-induced modifications on macroalgae that will allow us to tailor the forces of extraction to target specific molecules.

Innovative food processing technologies have been widely investigated in food processing research in recent years. These technologies offer key advantages for advancing the preservation and quality of conventional foods, for combatting the growing challenges posed by globalization, increased competitive pressures and diverse consumer demands. However, there is a need to increase the level of adoption of novel technologies to ensure the potential benefits of these technologies are exploited more by the food industry. This review outlines emerging thermal and non-thermal food processing technologies with regard to their mechanisms, applications and commercial aspects. The level of adoption of novel food processing technologies by the food industry is outlined and the factors that impact their industrial adoption are discussed. At an industry level, the technological capabilities of individual companies, their size, market share as well as their absorptive capacity impact adoption of a novel technology. Characteristics of the technology itself such as costs involved in its development and commercialization, associated risks and relative advantage, its level of complexity and compatibility influence the technology's adoption. The review concludes that a deep understanding of the development and application of a technology along with the factors influencing its acceptance are critical for its commercial adoption.

This study investigates ultrasound assisted extraction (UAE) process parameters (time, frequency and solvent) to obtain high yields of phlorotannins, flavonoids, total phenolics and associated antioxidant activities from 11 brown seaweed species. Optimised UAE conditions (35 kHz, 30 min and 50% ethanol) significantly improved the extraction yield from 1.5-fold to 2.2-fold in all seaweeds investigated compared to solvent extraction. Using ultrasound, the highest recovery of total phenolics (TPC: 572.3 ± 3.2 mg gallic acid equivalent/g), total phlorotannins (TPhC: 476.3 ± 2.2 mg phloroglucinol equivalent/g) and total flavonoids (TFC: 281.0 ± 1.7 mg quercetin equivalent/g) was obtained from Fucus vesiculosus seaweed. While the lowest recovery of TPC (72.6 ± 2.9 mg GAE/g), TPhC (50.3 ± 2.0 mg PGE/g) and TFC (15.2 ± 3.3 mg QE/g) was obtained from Laminaria digitata seaweed. However, extracts from Fucus serratus obtained by UAE exhibited the strongest 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity (29.1 ± 0.25 mg trolox equivalent/g) and ferric reducing antioxidant power (FRAP) value (63.9 ± 0.74 mg trolox equivalent/g). UAE under optimised conditions was an effective, low-cost and eco-friendly technique to recover biologically active polyphenols from 11 brown seaweed species.

Water, methanol and mixtures (20–80%) thereof have been used for the extraction of phenolic compounds from Irish brown seaweed Himanthalia elongata for studying its antimicrobial and antioxidant properties. The 60% methanolic extract exhibited significantly (P < 0.05) the highest value of yield (6.8 ± 0.24%), total phenol (286.0 ± 4.61 mg gallic acid equivalents/g), flavonoid (109.8 ± 2.68 mg quercetin equivalents/g) and condensed tannin content (35.6 ± 1.03 mg catechin equivalents/g). Antimicrobial activity of 60% methanolic extract tested from disc diffusion and broth dilution methods was effective against various food spoilage and pathogenic bacteria studied. The same extract exhibited statistically highest reducing power and antioxidant capacity against DPPH radical, metal ions, lipid peroxides and hydrogen peroxide radicals. The UV-visible spectroscopy showed absorption maxima at 205 and 260 nm and the presence of hydroxyl group (3,431 cm⁻¹) and an aromatic ring (around 1,465, 1,505 and 1,624 cm⁻¹) in Fourier Transform Infrared spectroscopy, suggested the presence of phenolic compounds in the extract. PRACTICAL APPLICATIONS In recent years, much attention has been focused on the use of natural preservatives to enhance the quality, safety and stability of ready-to-eat food products. These products also undergo gradual changes during storage, due to autoxidation, which releases reactive oxygen species including free radicals into the food. The consumption of seaweed as food and nutraceutical has been well known in the East. Nowadays, increasingly seaweeds are being investigated for the biological activity of their extracts which are finding hundreds of applications in pharmaceuticals, biotechnology and food preservatives. The present study demonstrates that H. elongata contains excellent antimicrobial and antioxidant properties which can provide opportunities for the application of seaweed extract as natural food preservative or nutraceutical for possible application in food and dietary supplemental products for health promotion.