Physicochemical Properties and Digestion Resistance of Acetylated Starch Obtained from Annealed Starch

One of the examples of physical starch modifications is the retention of a starch suspension in water having a temperature slightly lower than the pasting temperature (annealing). The aim of this study was to investigate the effect of the annealing process performed at various temperatures as the first stage of starch modification. The annealed starch preparations were then esterified using acetic acid anhydride. Finally, the annealed and acetylated starch preparations were determined for their properties. The annealing of starch before acetylation triggered changes in the properties of the modified preparations. It contributed to a higher degree of starch substitution with acetic acid residues and to the increased swelling power of starch. Both these properties were also affected by the annealing temperature. The highest resistance to amylolysis was found in the case of the starch preparation annealed at 53.5 °C and acetylated. The double modification involving annealing and acetylation processes increased the onset and end pasting temperatures compared to the acetylation alone. Similar observations were made for the consistency coefficient and yield point.

Effect of Sago Starch Modifications on Polystyrene/Thermoplastic Starch Blends

The preparation of polystyrene/thermoplastic starch (PS/TPS) blends was divided into three stages. The first stage involved the preparation of TPS from sago starch. Then, for the second stage, PS was blended with TPS to produce a TPS/PS blend. The ratios of the TPS/PS blend were 20:80, 40:60, 60:40, and 80:20. The final stage was a modification of the composition of TPS/PS blends with succinic anhydride and ascorbic acid treatment. Both untreated and treated blends were characterized by their physical, thermal, and surface morphology properties. The obtained results indicate that modified blends have better tensile strength as the adhesion between TPS and PS was improved. This can be observed from SEM micrographs, as modified blends with succinic anhydride and ascorbic acid had smaller TPS dispersion in PS/TPS blends. The micrograph showed that there was no agglomeration and void formation in the TPS/PS blending process. Furthermore, modified blends show better thermal stability, as proved by thermogravimetric analysis. Water uptake into the TPS/PS blends also decreased after the modifications, and the structural analysis showed the formation of a new peak after the modification process.

Starch modifications.

This chapter outlines the modification of tuber starches, the properties of modified starches, and the possible areas of application. The nature of modifications (physical, chemical, enzymatic, dual/triple modifications, graft polymerization) and their influence on the functional properties and structure of cassava, sweet potato, yam, aroid (Colocasia esculenta, Xanthosoma sagittifolium, Amorphophallus paeoniifolius and Arracacia xanthorrhiza) and other starches are described.

Impact of physical modifications on starch nutritional fractions: Rapidly Digestible Starch, Slowly Digestible Starch and Resistant Starch

The industrial utilization of native starches is limited because of their poor qualities and different starch modifications are used to improve functionality of starch. Physical modification of starch is preferred since it is simple, inexpensive, and specially it does not involve any chemical reagents. Physical modifications can be divided into thermal and non-thermal treatments. These techniques alter physicochemical properties of starch including in vitro digestibility, which indicates the nutritional value of starch. Starch nutritional fractions are of three types; RDS (rapidly digestible starch), SDS (slowly digestible starch) and RS (resistant starch). It is important to understand how physical modifications affect starch nutritional fractions as both SDS and RS have beneficial health effects and specially RS has the potential to be used as a natural bioactive compound. This review aims to summarize the recent knowledge regarding the physical modifications and their impact on in vitro digestibility and nutritional fractions of starch.

Karakterisasi Fisik Pati Tapioka Modifikasi Gabungan Hidroksipropilasi dengan Fosfat-Ikat Silang

Native tapioca starch has limited application in food industry due to its physicochemical characteristics that are not suitable for processing conditions, such as unstable at high temperature heating, acidic conditions, stirring, and undergoing syneresis. This deficiency can be overcome by applying a dual modification involving hydroxypropylation and cross-linking with phosphates. In this study, modification was carried out by hydroxypropylation using propylene oxide (8, 10, and 12%), followed by cross-linking with a combination of sodium tripolyphosphate (STPP) and sodium phosphate (STMP) with a ratio of 2%: 5%. The modified tapioca starch had water content of 7.82-8.19% with a pH value of 7.04-7.26, and phosphorus resiude of <0.4%. There were no change in starch granules and type of cristallline (A-tyype) of starch modifications. The dual modified starch with the addition of 10% propylene oxide concentration with a mixture of STMP : STTP ratio (2%:5% was selected to have acceptable physicochemical properties. It showed lowered pasting temperature, minimum break down viscosity, increased peak and setback viscosity compared to that of native starch. The modified tapioca starch also showed more heat stable and stirring resistant than that of native tapioca starch.

Acetylation and Evaluation of Taro Boloso-I Starch as Directly Compressible Excipient in Tablet Formulation

Taro Boloso-I (TB1), a newly improved Colocasia esculenta variety, is a potential source of starch with high yield. However, to improve some limitations of the native starches (NS), such as flowability and compactibility, different physical and chemical starch modifications have been employed. Acetylation is one of the chemical modifications which improves the flow and compaction of the NS, which are prerequisite during direct compression (DC) of tablets. Hence, in this study, TB1 starch was acetylated using acetic anhydride and evaluated as an ideal excipient for direct compression. Starch acetates (SA) with a degree of substitution (DS) of 0.072 (SA1) and 0.695 (SA2) were produced and evaluated. FTIR spectra of the SAs were used to verify the acetylation of the NS. Powder flow evaluation parameters showed significant improvement in the flow properties of the NS following acetylation. In addition, the swelling power, solubility, and compactibility were also improved. Tensile strength (TS) of the tablets comprising SAs only, SA1 (41.40) and SA2 (63.43 Kg/cm2), was significantly higher than tablets made of the NS (31.96) and Starch 1500® (15.12 Kg/cm2). The SAs also showed lower sensitivity towards lubrication than the NS and Starch 1500® as lower lubricant sensitivity ratios were recorded. In addition, tablets comprising the SAs satisfactorily accommodated at least up to 50 % w/w paracetamol—compared to 30 % w/w by Starch 1500®—upon DC processing. The paracetamol tablets comprising SAs also complied with the United States Pharmacopeia specifications for disintegration and dissolution studies. Therefore, taking all the facts into consideration, the SAs could be potential DC excipients in tablet formulations.