Morphology and different structural features of V-amylose complexes prepared with different concentrations (1%, 2%, 3%) of glycerol monostearate (GMS) and normal maize (NMS), waxy maize (WMS), and high amylose maize (HAMS) starches were evaluated using X-ray diffraction, differential scanning calorimetry, scanning electronic microscopy (SEM), atomic force microscopy (AFM), and transmission electronic microscopy (TEM). There was inclusion complex formation between all starches and GMS regardless of emulsifier concentration, with exception of WMS-2%GMS and WMS-3%GMS samples. All of the inclusion complexes displayed a V-type crystalline pattern and endothermic dissociation peaks between 115 and 120°C. They also displayed faceted crystalline structures with a tendency of the crystals to aggregate and form agglomerates of various sizes. TEM images of the complexes showed an aggregated strand structure interwoven with the GMS. Emulsifier and amylose quantities directly influenced complex formation. At high GMS concentrations, there was higher tendency of emulsifier to self-associate rather than form complexes with amylose.
Sour cassava starch is considered a modified starch used in many countries in several food products. Understanding modified starch granule structure is important in the knowledge of its physicochemical properties. Differential scanning calorimetry has been used to evaluate the effect of modifications on gelatinization of several starches. The aim of this work was to evaluate the structural characteristics and the gelatinization properties of commercial sour cassava starches with different total titratable acidity values, and to propose a new sour cassava starch classification by principal component analysis. Total titratable acidity of cassava starches varied from 2.16 to 6.74 %, which classified almost all samples as sour cassava starch. The sour cassava starches of classes from 1 to 4 showed low in iodine affinity and consequentially in apparent amylose content. Cassava starches with acidity ranging from 2.64 to 4.92 % (classes 1-4) displayed erosions on granule surface, high relative crystallinity, and high temperature and enthalpy gelatinization. Cassava starches with acidity above 4.99 % (classes 5 and 6) showed deeper erosions on granules, lower relative crystallinity and enthalpy, which indicated the beginning of degradation of the granule crystalline areas. Principal component analysis allowed verifying that the number of total titratable acidity classes could be reduced from 6 to 3, represented by groups with similar samples in relation to the structural and physicochemical behavior.
Overexploitation is a major threat for the integrity of marine ecosystems. Understanding the ecological consequences of different extractive practices and the mechanisms underlying the recovery of populations is essential to ensure sustainable management plans. Precious corals are long-lived structural invertebrates, historically overfished, and their conservation is currently a worldwide concern. However, the processes underlying their recovery are poorly known. Here, we examined harvesting effects and recovery mechanisms of red coral Corallium rubrum by analyzing long-term photographic series taken on two populations that were harvested. We compared the relative importance of reproduction and re-growth as drivers of resilience. Harvesting heavily impacted coral populations causing large decreases in biomass and strong size-class distribution shifts towards populations dominated by small colonies. At the end of the study (after 4 and 7 years) only partial recovery was observed. The observed general pattern of low recruitment and high mortality of new recruits demonstrated limited effects of reproduction on population recovery. Adversely, low mortality of partially harvested adults and a large proportion of colonies showing new branches highlighted the importance of re-growth in the recovery process. The demographic projections obtained through stochastic models confirmed that the recovery rates of C. rubrum can be strongly modulated depending on harvesting procedures. Thus, leaving the basal section of the colonies when harvesting to avoid total mortality largely enhances the resilience of C. rubrum populations and quickens their recovery. On the other hand, the high survival of harvested colonies and the significant biomass reduction indicated that abundance may not be an adequate metric to assess the conservation status of clonal organisms because it can underestimate harvesting effects. This study highlights the unsustainability of current harvesting practices of C. rubrum and provides urgently needed data to improve management practices that are still largely based on untested assumptions.
The objective of this study was to characterize the structural and physicochemical properties, the bioactive compounds and the antioxidant activity of freeze-dried açaí pulp (FDAP). The morphology of freeze-dried açaí pulp showed a continuous matrix with a spongey aspect, and the X-ray diffractometry indicated that 96.17% of the molecular structure was in the amorphous state and 3.82% in the crystalline state. Freeze-dried açaí pulp presented an interesting chemical composition of macronutrients, which constituted mainly of lipids (49.14 g/100 g d.b.), proteins (9.19 g/100 g d.b.), total crude fiber (20.29 g/100 g d.b.) and total sugars (2.71 g/100 g d.b.). Ot also showed great amount of total phenolic compounds (1405.03 mg gallic acid/100 g d.b.) and anthocyanins (127 mg cyanidine-3-glucoside/100 g d.b.), allowing for functional properties allegations. There was significant increase in the water absorption and water solubility indices when the freeze-dried açaí pulp was submitted to a gradual increase in temperature, properties that are adequate for industrial use. Thus, the consumption of freeze-dried açaí pulp should be encouraged and also its use by the food industry in order to develop new food products.
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