Fermentation and drying effects on bread-making potential of sour cassava and ahipa starches.

Cassava sour starch is a gluten-free product obtained by natural fermentation and sun-drying that outstrips the native starch baking expansion properties. Although maize starch has been subjected to a similar process, this desirable feature could not be achieved. Ahipa, an unexploited tuberous root, renders starch with relatively low gelatinization temperature and amylose content, like that of cassava. The aim of this work was to study the characteristics and technological properties of ahipa starch subjected to different fermentation processes and drying methods (oven- or sun-drying) and compare the bakery quality of its derived products to those from fermented cassava starches. Ahipa starch followed similar fermentation paths to those followed by cassava's, and sun-drying significantly reduced the content of the resultant lactic and butyric acids. Rheological behavior of starch pastes as well as moisture content and hardness of the doughs obtained from fermented and sun-dried ahipa starches differed from those of cassava. Sun-light exposure resulted detrimental for the expansion properties of ahipa sour starches, while the native one showed baking expansion properties like those of fermented sun-dried cassava starch. Thus, ahipa starch represents an interesting ingredient for the elaboration of gluten-free baked products.

Starch extraction process coupled to protein recovery from leguminous tuberous roots (Pachyrhizus ahipa).

The objective of this work was to fit together the starch extraction from Pachyrhizus ahipa roots and the recovery of the proteins present in these storage organs, making an improved use of this novel raw material. The replacement of water by buffer PO4(-3)/NaCl as solvent in the first extraction steps improved protein extraction without lowering the starch yield. The starches obtained from the traditional and the proposed methods exhibited some differences in appearance and technological and thermal properties, which were endorsed to the adjustment in the methodology of extraction rather than to the use of buffer as solvent. Thus, P. ahipa starch obtaining procedure could be coupled to protein extraction with a minimum change in the methodology. This innovation did not significantly shift the characteristics of the starch obtained and allowed to obtain a protein yield of 135.7mg BSA equivalent protein/100g of fresh roots.

Nutritional and sensory quality during refrigerated storage of fresh-cut mints (Mentha×piperita and M. spicata).

The effect of storage time on quality attributes of refrigerated fresh-cut mints (Mentha×piperita and M. spicata) was studied. Atmosphere composition, respiratory activity, weight loss, surface colour, total chlorophyll, carotenoids, browning potential, total phenols, flavonoids, radical-scavenging activity, ascorbic acid and essential oil yield and composition were analysed. Respiratory activity of peppermint and spearmint samples diminished moderately (42% and 28%, respectively) after 21days at 0°C. A slight modification of the internal atmosphere was achieved. Surface colour, chlorophyll, carotenoid and antioxidant compounds remained almost constant. The yield of essential oil did not change or it showed an apparent increase after 21days at 0°C, depending on plant growth stage. The characteristic flavour components of peppermint (menthone and menthol) increased, while the contents of the main constituents of spearmint essential oil showed minor variations after storage. The conditions assayed for packaging and storing fresh-cut mints were adequate to achieve a relatively long shelf life and they retained their antioxidant properties.

Pachyrhizus ahipa (Wedd.) Parodi roots and flour: Biochemical and functional characteristics.

Ahipa roots' chemical composition and physiological parameters were characterised; ahipa flour preparation procedures were selected and the chemical composition and functional properties of these products were studied. Ahipa roots and flour can be considered alternative food sources of gluten-free starch, with a considerable contribution of protein, fibre and minerals, such as potassium, calcium and iron. The grating process for ahipa flour production required a pressing step (AFGP) and the recovery of the starch leached. The slicing procedure (AFS) was simpler and the resulting product showed higher contents of potassium, magnesium, calcium and protein than did AFGP, which showed lower sodium and higher acid detergent fibre contents, together with lower gelatinisation temperature. Both flours differed in terms of α-amylase activity and swelling power, characteristics that may condition their specific applications, such as the incorporation of these flours as gluten-free functional food ingredients.