Underpinning beneficial maize response to application of minimally processed homogenates of red and brown seaweeds.

Sap from the fresh seaweed Kappaphycus alvarezii (KA) has been reported to improve crop growth, quality, and stress alleviation. However, limited studies are reported for the minimally processed aqueous homogenates (MPHs) derived from dry seaweeds. The present investigation was envisaged to characterize the MPHs from the red seaweed KA and a brown seaweed Sargassum wightii (SW) and also assess the effect of foliar application on maize (Zea mays) crop performance when applied alone or in proportions ranging from 0% to 100%. Two doses (0.35% and 0.7%) were compared with control. Both the MPHs contained several compounds like retronecine, tyrosyl-glycine, hexyl 2-furoate, 1-phosphatidyl-1D-myo-inositol, 12-(2,3-dihydroxycyclopentyl)-2-dodecanone, and trihomomethionine and many others that have known bioactivity for enhancing plant growth and providing stress tolerance. Both doses of MPHs enhanced crop growth and yield; however, the best response was in general observed at a lower dose. The MPH of SW at 100% gave the highest seed yield at a lower dose, which was also on par with that obtained under a lower dose of 100% KA. Other combinations, 80:20 and 40:60 KA : SW, were also found to give comparable yields. The highest dose of 100% MPH of SW was found on par with control, a phenomenon that was investigated in detail with respect to metabolites and antioxidant profile in leaves as well as membrane modeling. Higher ROS and certain sugar and organic acids were observed in 100% MPH of SW at a higher dose, although none of the antioxidant enzymes were significantly affected, nor was there any change in membrane characteristics of the leaf with respect to control as well as lower dose. Improvements in the seed yield were attributed to improved photosynthate production on account of higher dry matter accumulation in the MPH-treated plants, which may also be attributed to the presence of bioactive compounds in the biostimulants. In the future, it is imperative to direct scientific investigations towards the quantification and identification of the most effective concentrations of these compounds within MPHs to optimize plant responses. The study indicated the beneficial use of the MPHs towards increasing crop production by employing optimum dose as foliar spray to crops.

Phycoerythrin: a pink pigment from red sources (rhodophyta) for a greener biorefining approach to food applications.

Phycoerythrin (PE) is a photosensitive red pigment from phycobiliprotein family predominantly present in the red algae. The concentration of PE depends on photon flux density (PFD) and the quality of light absorbed by the algae tissue. This necessitates robust techniques to extract PE from the embedded cell-wall matrix of the algal frond. Similarly, PE is sensitive to various factors which influence its stability and purity of PE. The PE is extracted from Red algae through different extraction techniques. This review explores an integrative approach of fractionating PE for the scaling-up process and commercialization. The mechanism for stabilizing PE pigment in food was critically evaluated for further retaining this pigment within the food system. The challenges and possibilities of employing efficient extraction for industrial adoption are meticulously estimated. The techniques involved in the sustainable way of extracting PE pigments improved at a laboratory scale in the past decade. Although, the complexity of industrial-scale biorefining was found to be a bottleneck. The extraction of PE using benign chemicals would be safe for food applications to promote health benefits. The precise selection of encapsulation technique with enhanced sensitivity and selectivity of the membrane would bring better stability of PE in the food matrix.

Producing novel edible films from semi refined carrageenan (SRC) and ulvan polysaccharides for potential food applications.

Edible films were developed from seaweed polysaccharides (Kappaphycus alvarezii and Ulva fasciata). The total extracted yield of semi refined carrageenan (SRC) and ulvan polysaccharide was 31.55%, and 28.86%, with total carbohydrate being 78.08% and 82.43% in SRC and ulvan polysaccharides. Results of viscometric studies revealed molecular weight to be 210kDa and 72kDa for SRC and ulvan polysaccharides. Proton NMR studies showed presence of anhydro-d-galactopyranose and glucosidic linkages in SRC, while ulvan polysaccharide had rhamnose-3-sulfate, glucosyl and ß-d-glucuronic acid. Three different films developed from SRC and ulvan polysaccharides [SRC, ulvan polysaccharide and combination of SRC and ulvan polysaccharide films] with glycerol. FT-IR spectra confirmed functional group of all the edible films which corresponds with NMR results. Water vapor permeability of films indicated a range of 7.82 to 9.96×10-8gm-1s-1Pa-1 with high tensile strength varying between 36.78 and 49.12MPa. Results on antioxidant activity indicated a strong hydroxyl radical scavenging activity detected in ulvan polysaccharide based film, while metal ion chelating activity was higher in films with a combination of SRC and ulvan polysaccharides. Further, low molecular weight films had better antioxidant activity, while high molecular weight films possessed good mechanical properties.