Optimization of Ultrasonic Extraction Parameters for the Recovery of Phenolic Compounds in Brown Seaweed: Comparison with Conventional Techniques

Seaweed, in particular, brown seaweed, has gained research interest in the past few years due to its distinctive phenolic profile that has a multitude of bioactive properties. In order to obtain the maximum extraction efficiency of brown seaweed phenolic compounds, Response Surface Methodology was utilized to optimize the ultrasound-assisted extraction (UAE) conditions such as the amplitude, time, solvent:solid ratio, and NaOH concentration. Under optimal conditions, UAE had a higher extraction efficiency of free and bound phenolic compounds compared to conventional extraction (stirred 16 h at 4 °C). This led to higher antioxidant activity in the seaweed extract obtained under UAE conditions. The profiling of phenolic compounds using LC-ESI-QTOF-MS/MS identified a total of 25 phenolics with more phenolics extracted from the free phenolic extraction compared to the bound phenolic extracts. Among them, peonidin 3-O-diglucodise-5-O-glucoside and hesperidin 5,7-O-diglucuronide are unique compounds that were identified in P. comosa, E. radiata and D. potatorum, which are not reported in plants. Overall, our findings provided optimal phenolic extraction from brown seaweed for research into employing brown seaweed as a functional food.

Unraveling the bioactive interplay: seaweed polysaccharide, polyphenol and their gut modulation effect

Seaweed is rich in many unique bioactive compounds such as polyphenols and sulfated polysaccharides that are not found in terrestrial plant. The discovery of numerous biological activities from seaweed has made seaweed an attractive functional food source with the potential to be exploited for human health benefits. During food processing and digestion, cell wall polysaccharide and polyphenols commonly interact, and this may influence the nutritional properties of food. Interactions between cell wall polysaccharide and polyphenols in plant-based system has been extensively studied. However, similar interactions in seaweed have received little attention despite the vast disparity between the structural and chemical composition of plant and seaweed cell wall. This poses a challenge in extracting seaweed bioactive compounds with intact biological properties. This review aims to summarize the cell wall polysaccharide and polyphenols present in brown, red and green seaweed, and current knowledge on their potential interactions. Moreover, this review gives an overview of the gut modulation effect of seaweed polysaccharide and polyphenol.

Palm-based cellulose nanofiber isolated from mechano-chemical processing as sustainable rheological modifier in reduced fat mayonnaise

Abstract

Reducing fat intake from our daily diet serves to be an effective way to combat the rising obesity issue worldwide. Hence, reducing fat content in mayonnaise, a high fat food product, is one of the primary trends in the food industry. To date, research on the use of nanocellulose, a new and emerging form of fat mimetic, in mayonnaise formulation remains limited. This study sets out to formulate reduced fat 5%, 15%, and 30% mayonnaise using varying concentration of nanocellulose synthesized from palm pressed fiber followed by a 20‐day stability study. Nanocellulose was synthesized with particle size of 106.0 ± 18.7 nm and zeta potential of −72.5 ± 2.26 mV. It was used as fat mimetic in mayonnaise. Rheological analysis conducted showed that incorporation of nanocellulose into reduced fat mayonnaise formulation was able to counteract the loss of viscosity in mayonnaise caused by fat content reduction. This finding was further supported by the smaller oil droplets that are closely packed in reduced fat mayonnaise formulation when viewed under light microscope. Nonetheless, significant oil droplet coalescence was found in reduced fat mayonnaise formulations during storage period which could lead to loss of viscosity. Taken together, these findings suggest that CNF was able to act as fat mimetic upon formulation of mayonnaise but the same cannot be said during long term storage of mayonnaise.

Practical Application

We successfully isolated nanocellulose from palm biomass (palm pressed fiber) using green approach and used it as a fat replacer for preparation of 5%, 15%, and 30% reduced fat mayonnaise. A computation study revealed a strong binding affinity of the nanocellulose on the lipase active site essential to inhibit the digestion of fats and oils. Therefore, nanocellulose demonstrated a huge potential to be used as not only as fat replacer but also rheological modifier for the development of reduced fat or vegan foods.