In vitro glycemic index, physicochemical properties and sensory characteristics of white bread incorporated with resistant starch powder prepared by a novel spray-drying based method

Starch-guest complexes interactions: Molecular mechanisms, effects on starch and functionality

Starch is a natural, abundant, renewable and biodegradable plant-based polymer that exhibits a variety of functional properties, including the ability to thicken or gel solutions, form films and coatings, and act as encapsulation and delivery vehicles. In this review, we first describe the structure of starch molecules and discuss the mechanisms of their interactions with guest molecules. Then, the effects of starch-guest complexes on gelatinization, retrogradation, rheology and digestion of starch are discussed. Finally, the potential applications of starch-guest complexes in the food industry are highlighted. Starch-guest complexes are formed due to physical forces, especially hydrophobic interactions between non-polar guest molecules and the hydrophobic interiors of amylose helices, as well as hydrogen bonds between some guest molecules and starch. Gelatinization, retrogradation, rheology and digestion of starch-based materials are influenced by complex formation, which has important implications for the utilization of starch as a functional and nutritional ingredient in food products. Controlling these interactions can be used to create novel starch-based food materials with specific functions, such as texture modifiers, delivery systems, edible coatings and films, fat substitutes and blood glucose modulators.

Dynamic rheological behavior of high-amylose wheat dough during various heating stages: Insight from its starch characteristics

The objective of this study was to understand how the dynamic rheological behaviors of high-amylose wheat (HAW) dough during various heating stages measured using a mixolab were affected by the starch properties. At the heating stage of 30 °C - 90 °C, low minimum (C2) and peak (C3) torques were observed for HAW doughs, which resulted from their reduced starch granule swelling. During holding at 90 °C, HAW doughs had low minimum (C4) and C3 - C4 torques, indicating a good resistance to mechanical shear and endogenous enzyme degradation. HAW doughs also had low final (C5) and setback (C5 - C4) torques, consistent with their low starch swelling power and solubility. The increased amylose in HAW starch formed long-chain double-helical B-type polymorph and amylose-lipid complex, which resulted in high starch gelatinization-temperatures and enthalpy change, low swelling power and solubility, low pasting viscosity, and high resistance of swollen granules to mechanical shear and enzyme degradation. The overall patterns of dough-rheological behavior of HAW doughs during heating were similar to their respective starch pasting profiles, indicating that starch was the dominant contributor to the dough rheology during heating. This study provides useful information for food applications and manufacturing of HAW-based products, especially none-fermented products requiring firm texture and low viscosity.

Understanding the mechanisms of β-glucan regulating the in vitro starch digestibility of highland barley starch under spray drying: Structure and physicochemical properties

This study investigated the effects of β-glucan (0-6%) on the physicochemical properties, structure, and in vitro digestibility of highland barley starch (HBS) under spray drying (SD). SD significantly enhanced the inhibitory effect of 6% β-glucan on the in vitro digestibility and glucose diffusion of HBS. After SD, the addition of β-glucan at 4% and 6% concentration significantly increased the pasting temperatures of starch while decreased the rheological properties. Thermal properties demonstrated that β-glucan improved the thermal stability and residue content of HBS at 600°C, lowered its maximum loss rate, and maintained its thermal stability after SD. Structural properties showed that β-glucan affected greatly on amorphous regions of HBS after SD. Additionally, β-glucan dispersed more evenly in the starch system and experienced hydrogen bonding with starch after SD. This study presents a novel approach to enhancing the inhibitory effect of β-glucan on starch digestion.

The impact of addition of pearl millet starch-germ complex in white bread on nutritional, textural, structural, and glycaemic response: Single blinded randomized controlled trial in healthy and pre-diabetic participants

The rise of pre-diabetes at the global level has created a significant interest in developing low glycaemic index food products. The pearl millet is a cheaper source of starch and its germ contains significant amount of protein and fat. The complexing of pearl millet starch and germ by dry heat treatment (PMSGH) resulted an increase in the resistant starch content upto 45.09 % due to formation of amylose-glutelin-linoleic acid complex. The resulting pearl millet starch germ complex was incorporated into wheat bread at 20, 25, and 30 %. The PMSGH incorporated into bread at 30 % reduced the glycaemic index to 52.31. The PMSGH incorporated bread had significantly (p < 0.05)increased in the hardness with a reduction in springiness and cohesiveness. The structural attributes of the 30 % PMSGH incorporated bread revealed a significant (p < 0.05)increase in 1040/1020 cm-1 ratio and relative crystallinity. The consumption of functional bread incorporated with pearl millet starch germ complex reduced blood glucose levels and in vivo glycaemic index in healthy and pre-diabetic participants when compared to white bread. Hence, the study showed that the incorporation of pearl millet starch-germ complex into food products could be a potential new and healthier approach for improving dietary options in pre-diabetes care.

Development and analysis of a multi-module peristaltic simulator for gastrointestinal research

Many existing in vitro digestion systems do not accurately represent the peristaltic contractions of the gastrointestinal system; most of the systems that have physiologically-relevant peristaltic contractions have low throughput and can only test one sample at a time. A device has been developed that provides simulated peristaltic contractions for up to 12 digestion modules simultaneously using rollers of varying width to modulate the dynamics of the peristaltic motion. The force applied to a simulated food bolus varied from 2.61 ± 0.03 N to 4.51 ± 0.16 N (p < 0.05) depending on roller width. Video analysis showed that the degree of occlusion of the digestion module varied from 72.1 ± 0.4% to 84.6 ± 1.2% (p < 0.05). A multiphysics, computational fluid dynamics model was created to understand the fluid flow. The fluid flow was also examined experimentally using video analysis of tracer particles. The model-predicted maximum fluid velocity in the peristaltic simulator incorporating the thin rollers was 0.016 m/s, and the corresponding value measured using tracer particles was 0.015 m/s. The occlusion, pressure, and fluid velocity in the new peristaltic simulator fell within physiologically representative ranges. Although no in vitro device perfectly recreates the conditions of the gastrointestinal system, this novel device is a flexible platform for future gastrointestinal research and could allow for high-throughput screening of food materials for health-promoting properties under conditions representative of human gastrointestinal motility.

Physicochemical characteristics and in vitro digestibility of starches from colored quinoa (Chenopodium quinoa) varieties

The quinoa flour processing is mostly subject to the properties of starch. Starches from four colored quinoa varieties, including white quinoa (QS-W), yellow quinoa (QS-Y), red (QS-R), and black (QS-B), were compared with respect to their physicochemical properties and in vitro digestibility. Results indicated that QS-B exhibited the highest content of amylose (8.14%) (p < 0.05). All starch samples exhibited as irregular sphere with a particle size less than 3 µm. Results of the FT-IR and X-ray showed that the short-range order of the four quinoa starches exhibited no significant difference; all starches showed a typical A-type diffractrometric pattern and was not affected by seed color, and QS-Y had the highest relative crystallinity (34.3%) (p < 0.05). In addition, QS-W reflected the highest solubility (6.32%) and QS-Y showed the highest swelling power (19.45 g/g) (p < 0.05). QS-Y also presented a higher ΔH value (11.46 J/g) (p < 0.05), while QS-R peak temperature and peak G' were the lowest. Besides, QS-B had the highest slow-digestible starch (SDS) and resistant starch (RS) content, while the lowest estimated glycemic index (eGI) value (p < 0.05). Also, there was a negative correlation between hydrolysis rates and amylose content of quinoa starch. PRACTICAL APPLICATION: Due to the low gelatinization temperature of quinoa starch, it can be used to both produce and improve instant and fast food products. Quinoa starch particles are small, and Pickering emulsions and additives have potential application values. Red quinoa contains easily digestible starch, which can be a good food choice for infants and the elderly, while white quinoa starch has less swelling power and can be used in noodle products. The results of this study can help to underpin the study of quinoa nonstarch components versus starch component.