Hawthorn fruits (Crataegus pinnatifida) present high content of high-methoxyl pectin, able to gel under highsugar acidic conditions. In this work, the proximate and phytochemical composition of two cultivars of hawthorn fruit and the gelling ability of their unrefined (not further processed) dried powders and their extracted pectins were evaluated and systematically compared with citrus pectins (CP1 and CP2). Mianqiu (MI), a less known cultivar, showed two-fold higher pectin content and titratable acidity than Dajinxing (DA), one of the most common cultivars. DA showed higher starch, insoluble dietary fiber, pasting viscosity and total and extractable (EPP) phenolic compounds. EPP content was almost two-fold higher in DA than MI, resulting in stronger antioxidant properties. All high-methoxyl sugar acid gels exhibited a predominantly elastic response. MI resulted in hawthorn-powder gels with higher elastic modulus (G ') after gel-making (initially stronger gels), and lower G ' increase during storage (hardening) than DA. Citrus pectins (CP2 > CP1) showed higher gel-strength and faster gelling ability than hawthorn pectin gels (DA > MI) based on the lower G' and lack of gel formation after 90 min of cooling in hawthorn pectin-based gels. The gelation results were closely linked to the starch-to-pectin ratio, purity, and degree of methyl esterification.

Starch from bananas/plantains, belonging to the genus Musa spp, is gaining prominence given its great potential as a healthy food ingredient made from an inexpensive raw material. Recent works highlight the outstanding potential of Musa starch to develop enzyme-resistant structures upon retrogradation. However, despite the wide variety of Musa cultivars (due to both natural mutation and breeding selection), there is no comparative investigation of the starch molecular structure from the most commonly cultivated Musa genotypes. In this work, the starch from six Musa cultivars harvested during the same growing season from the same parcel, was purified and analyzed for amylose ratio, amylose chain length distribution, and amylopectin unit and internal chain length distribution. Results showed significant differences between the fine structure of all Musa amylopectin molecules, which were structurally categorized as type 4 (consisting of a high number of B3-chains, few BS- and B-fp-chains, and low S:L and BS:BL ratios). Moreover, the different Musa starches exhibited dramatic differences in amylose ratio (17.7-27.6%), amylose branching degree (as evidenced by differences in the population of short chains of approximately 260 glucose units, GU) and a shorter average length (approximately 1000 GU) of the population of long amylose unit chains. Remarkably, these differences in amylose structure resulted in the cultivar Manzano (Musa AAB, silk subgroup) to possess a dramatically lower extension of in vitro starch digestion (C-90 = 4.70%) than the rest of the cultivars (C-90 = 17-18%) after full gelatinization and retrogradation for 7 days.

A structure-digestion model is proposed to explain the formation of α-amylase-slowly digestible structures during amylopectin retrogradation. Maize and potato (normal and waxy) and banana starch (normal and purified amylopectin through alcohol precipitation), were analyzed for amylose ratio and size (HPSEC) and amylopectin unit- and internal-chain length distribution (HPAEC). Banana amylopectin (BA), like waxy potato (WP), exhibited a larger number of B3-chains, fewer BS- and Bfp-chains and lower S:L and BS:BL ratios than maize, categorizing BA structurally as type-4. WP exhibited a significantly greater tendency to form double helices (DSC and 13C-NMR) than BA, which was attributed to its higher internal chain length (ICL) and fewer DP6-12-chains. However, retrograded BA was remarkably more resistant to digestion than WP. Lower number of phosphorylated B-chains, more S- and Bfp-chains and shorter ICL, were suggested to result in α-amylase-slowly digestible structures through further lateral packing of double helices (suggested by thermo-rheology) in type-4 amylopectins.

The rapid proliferation of cyanobacteria in bodies of water has caused cyanobacterial blooms, which have become an increasing cause of concern, largely due to the presence of toxic secondary metabolites (or cyanotoxins). Cyanotoxins are the toxins produced by cyanobacteria that may be harmful to surrounding wildlife. They include hepatotoxins, neurotoxins and dermatotoxins, and are classified based on the organs they affect. There are also non-toxic secondary metabolites that include chelators and UV-absorbing compounds. This paper summarizes the optimal techniques for secondary metabolite extraction and the possible useful products that can be obtained from cyanobacteria, with additional focus given to products derived from secondary metabolites. It becomes evident that the potential for their use as biocides, chelators, biofuels, biofertilizers, pharmaceuticals, food and feed, and cosmetics has not yet been comprehensively studied or extensively implemented.