Stored Gelatinized Waxy Potato Starch Forms a Strong Retrograded Gel at Low pH with the Formation of Intermolecular Double Helices.

Waxy potato amylopectin has longer internal and external linear chains than rice or corn amylopectin that are capable of retrograding to a higher degree, but its molecular recrystallization is impeded by unprotonated phosphate groups. Here, we studied whether retrogradation and gel properties of waxy potato starch can be enhanced by lowering pH. The gel strength of waxy potato starch was strongly inversely correlated with pH, going from 10 to 4, and its magnitude was higher at pH values in which the ζ potential of the system was low. Waxy potato starch formed a strong aggregate gel driven by the formation of intermolecular double helices (G' drop25-95 °C ≈ 1358 Pa, melting ΔH = 9.5 J/g) when conditions that reduce electrostatic repulsion (pH 4, ζ = -1.7) are used, a phenomenon that was not observed in low-phosphorylated waxy cereal starches (i.e., waxy rice and corn).

Disease concepts and treatment practices relating to schistosomiasis haematobium in Upper Egypt.

Disease concepts and medical treatment practices surrounding schistosomiasis haematobium were studied among males in Upper Egyptian villages and towns using interview methods. Most informants considered bilharzia to be a serious disease for which they commonly sought treatment. Its occurrence was attributed primarily to natural causes, particularly various aquatic worms and insects, dirts, excrement, dead animals, toxins and stagnant and vegetated waters, mostly large canals. Contact with water from the Nile river was generally thought to be quite safe. Drug treatment was weakly associated with amount of education. All groups reported use of antischistosomal drugs and plant medicines. Seventy-four per cent of the sample had a treatment history, 64% having taken oral drugs and/or injections, 40% plant medicines and 29% both. Drinking decoctions of damsissa (Ambrosia maritima) was the most commonly used household remedy. Plant materials were usually obtained from fields, gardens and local markets and patent medicines from nearby clinics and private physicians in towns. Recommendations are made for the national mass chemotherapy programme.