Corn and Pinhão Starches Modified with Sodium Tripolyphosphate: Thermal, Pasting, Structural and Morphological Properties

Abstract

Pinhão and corn starches are submitted to phosphating with sodium tripolyphosphate and their properties are evaluated by thermogravimetry, differential scanning calorimetry, viscoamylography, X‐ray powder diffractometry, field emission gun‐scanning electron microscopy analysis. The phosphating process is divided into three steps to analyse the behaviour of the sample on exposure to phosphate groups. After the modification, there is a decrease in the transition temperatures and gelatinisation enthalpy of both starches. During the three phases of phosphating, small differences are observed in the thermal stability of the modified samples, but a lower value is obtained for corn starch after the third stage. The decrease in pasting temperature is accompanied by an increase in the peak viscosity of the starch suspensions, however, higher values for setback and breakdown are also recorded. The degree of relative crystallinity of the phosphated starches increases, and from microscopy it is possible to observe the presence of crystals of sodium tripolyphosphate during phosphating process.

Effect of Ball Milling Treatment on Thermal, Structural, and Morphological Properties of Phosphated Starches from Corn and Pinhão

“…reported phosphorus levels of 0.035%, 0.022%, and 0.024% for starches from three cultivars of yam ( Dioscorea rotundata ). The phosphorus content of the samples determined by WDXRF was slightly higher than that detected by the colorimetric method at 725 nm . A similar relationship was presented by Noda et al .…”

“…The seeds were manually peeled and the embryo was removed. The pinhão starch was extracted by aqueous process . The corn starch (Maiscerta, lot 03/16/17) was acquired in the local market of Ponta Grossa‐PR.…”

“…Pinhão and corn starch were modified in low concentration (5%) of STPP, according to the steps described in detail in our previous study …”

“…Araucaria angustifolia seed, called pinhão, is an unconventional source of starch . The proximal composition of the seed reveals its great nutritional value.…”

“…In our previous study, pinhão starch was chemically modified with sodium tripolyphosphate (STPP) and its pasting, thermal, morphological, and structural properties were evaluated. Phosphating decreased the pasting temperature and enthalpy but increased the final viscosity and the relative crystallinity (RC) of pinhão starch.…”