Structural Transformation of Sago Starch by Heat-Moisture and Osmotic-Pressure Treatment

Characteristics of rice starches modified by single and dual heat moisture and osmotic pressure treatments

The effect of osmotic pressure treatment (OPT), heat moisture treatment (HMT), and their dual combination as HMT-OPT and OPT-HMT on functional and pasting properties, gel texture, crystallinity, thermal, morphological, and rheological properties, and in vitro digestibility of modified starches were investigated. HMT was done with 29 % moisture at 111 °C for 45 min while OPT was performed at 117 °C for 35 min with saturated sodium sulphate solution. All modifications increased amylose content, improved pasting stability, and reduced swelling power and solubility. Dual modifications caused higher morphological changes than single modified starches. HMT and OPT increased pasting temperature, setback and final viscosity while decreased peak viscosity and breakdown, whereas HMT-OPT and OPT-HMT reduced all pasting parameters except pasting temperature. 1047/1022 and 995/1022 ratios and relative crystallinity decreased. V-type polymorphs were formed, and gelatinization temperature range increased with lower gelatinization enthalpy. Starch gel elasticity, RS and SDS content were enhanced to a greater extent after HMT-OPT and OPT-HMT. HMT as a single and dual form with OPT showed prominent effect on pasting, thermal, crystalline, and rheological properties. Application of HMT, OPT and dual modified starches with improved functionalities may be targeted for suitable food applications such as noodles.

Dual Modification of Sago Starch via Heat Moisture Treatment and Octenyl Succinylation to Improve Starch Hydrophobicity

To elucidate the pretreatment of a heat moisture treatment that could increase the DS and hydrophobicity of OSA starch, the effect of the moisture level of the HMT process on the physicochemical properties was investigated. The higher moisture content (MC) in the HMT process led to a decreasing degree of crystallinity and gelatinization enthalpy and also produced surface damage and cracking of the granules. HMT pretreatment with the right moisture content resulted in OSA starch with the maximum DS value and reaction efficiency. Pre-treatment HMT at 25% MC (HMT-25) followed by OSA esterification exhibited the highest DS value (0.0086) and reaction efficiency (35.86%). H25-OSA starch has been shown to have good water resistance (OAC 1.03%, WVP 4.92 × 10-5 g/s m Pa, water contact angle 88.43°), and conversely, has a high cold water solubility (8.44%). Based on FTIR, there were two new peaks at 1729 and 1568 cm-1 of the HMT-OSA starch, which proved that the hydroxyl group of the HMT starch molecule had been substituted with the carbonyl and carboxyl ester groups of OSA.

Pressure moisture treatment and hydro-thermal treatment of starch

Starch is often subjected to denaturation treatment to improve its useful properties and eliminate its shortcomings. Various methods have been developed to produce modified starches with different properties and for a variety of uses. Because physically modified starch can be produced without chemical substances or biological agents, the modification method is very simple and inexpensive, and the resulting material can be used as clean label starch. Among these physical modification technologies, heat moisture treatment (HMT) is a universally valid technology, but little is known about pressure moisture treatment (PMT)-related technology. Physical modification of starch using PMT results in new functions and value-added characteristics required by industry, and PMT has the potential to produce starch with new functions. In this paper, PMT-related technologies for physically modified starch, the difference between PMT and the hydro-thermal treatment, and clean label starch manufacturing using HMT and PMT were investigated.

The effect of different thermal modifications on slowly digestible starch and physicochemical properties of green banana flour (Musa acuminata colla)

The effect of heat moisture treatment (HMT), annealing (ANN), and dual retrogradation (DR) on functional and pasting properties, digestibility of starch components of banana flour comprising rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) has been investigated, using native banana flour (NBF) as a control. Crystal type, relative crystallinity and morphological changes were characterised by XRD and SEM. HMT has markedly modified the pasting properties and resulted in the highest SDS content. HMT and ANN increased the relative crystallinity but DR decreased it. HMT and DR altered XRD patterns from B to A and A + B type respectively, while ANN did not change the XRD patterns. The NBF compact granule surface remained unchanged with ANN but changed to a more porous surface with HMT and DR, thereby increasing the digestibility. Crystal type and granule morphology affected the digestibility while relative crystallinity might change the pasting point.

Non-starch contents affect the susceptibility of banana starch and flour to ozonation

The properties of native flour and starch were compared and the changes in their properties were evaluated following ozonation at 100 and 200 ppm. X-ray diffraction analysis indicated that crystallinity index of both ozonated banana flour and starch decreased by 1.6%, B-type pattern of native banana flour and starch did not change following ozonation. The presence of higher amounts of non-starch components decreased the sensitivity of flour to the oxidation, as indicated by the lower carboxyl content compared to that of starch. The flour also required higher ozone concentration than starch to alter its properties, particularly pasting properties. Ozonation tended to increase peak, hold and final viscosity of both. A prominent change in the freeze thaw stability of both flour and starch following ozonation was the most encouraging result. Ozonation also improved the solubility of flour which was important to reduce cooking loss when applied in a range of food products. The solubility improvement in the flour might be linked to the formation of new binding following ozonation presumably involving protein present in the granule surface.

A comparison of the effects of heat moisture treatment (HMT) on rheological properties and amylopectin structure in sago (Metroxylon sago) and arenga (Arenga pinnata) starches

The objective of this study was to study and compare the impact of HMT on rheology and textural properties observed between sago and arenga starces, and then related to structural change of amylopectin. The HMT were conducted using the autoclaving method at 20% moisture content and heated to 120 C for 60 min for sago and 90 min for arenga starch as optimum condition. The HMT shifted gelatinization temperature higher and reduced the enthalpy of both starches. The HMT sago starch paste exhibited an exceptionally strong shear thinning behavior as shown by a rapid decrease of viscosity and an increase of shear rate. The HMT clearly made the texture of starch gels more fragile compared to their native form and reduced their breaking point to a lower strain. The HMT effect on the rheological properties and texture of the sago starch was greater than the changes observed with the arenga starch. Major changes in rheological properties after HMT was not followed by changes in amylopectin structure. The HMT process did not significantly affect the amylopectin chain-length distribution in Arenga starch. In the sago starch, HMT affect to long chain amylopectin with DP ≥ 37. The HMT effect on rheology and textural properties was higher in sago starch than arenga starch. This study demonstrated that long chain amylopectin with DP ≥ 37 plays an important role in contributing to the rheological change caused by the HMT.

The impact of heat-moisture treatment on molecular structures and properties of starches isolated from different botanical sources

Heat-moisture treatment is a hydrothermal treatment that changes the physicochemical properties of starches by facilitating starch chain interactions within the amorphous and crystalline domains and/or by disrupting starch crystallites. The extent of these changes is influenced by starch composition, moisture content and temperature during treatment, and by the organization of amylose and amylopectin chains within native starch granules. During heat-moisture treatment starch granules at low moisture levels [(<35% water (w/w)] are heated at a temperature above the glass transition temperature (T(g)) but below the gelatinization temperature for a fixed period of time. Significant progress in heat-moisture treatment has been made during the last 15 years, as reflected by numerous publications on this subject. Therefore, this review summarizes the current knowledge on the impact of heat-moisture treatment on the composition, granule morphology, crystallinity, X-ray pattern, granular swelling, amylose leaching, pasting properties, gelatinization and retrogradation parameters, and susceptibility towards α-amylase and acid hydrolysis. The application of heat-moisture treatment in the food industry is also reviewed. Recommendations for future research are outlined.