Formation of debranched wheat starch-fatty acid inclusion complexes using saturated fatty acids with different chain length

Effect of different chain-length fatty acids on the retrogradation properties of rice starch

In order to delay the retrogradation of rice starch, the effects of three different chain length fatty acids (lauric acid, myristic acid and palmitic acid) on rice starch were studied. The fatty acids with longer carbon chains had strong steric hindrance and hydrophobicity, which formed a more compact structure in the helical cavity of amylose, and significantly reduced degree of expansion, migration of water, short-range ordered structure, number of double helical structures and crystallinity. These structural changes endowed the rice starch-long chain fatty acid complexes with better gel viscosity, liquid fluidity and thermal stability than in the rice starch-short chain fatty acid complexes. The results showed that fatty acids with longer chain length inhibited the retrogradation of rice starch, most obviously when 5% palmitic acid was added. This study provides an important reference for the processing of rice starch-based foods.

Study on multiscale structures and digestibility of cassava starch and medium-chain fatty acids complexes using molecular simulation techniques

Effect of complexation of three medium-chain fatty acids (octanoic, decylic and lauric acid, OA, DA and LA, respectively) on structural characteristics, physicochemical properties and digestion behaviors of cassava starch (CS) was investigated. Current study indicated that LA was more easily to combine with CS (complex index 88.9%), followed by DA (80.9%), which was also consistent with their corresponding complexed lipids content. Following the investigation of morphology, short-range ordered structure, helical structure, crystalline/amorphous region and fractal dimension of the various complexes, all cassava starch-fatty acids complexes (CS-FAs) were characterized with a flaked morphology rather than a round morphology in native starch (control CS). X-ray diffraction demonstrated that all CS-FAs had a V-type crystalline structure, and nuclear magnetic resonance spectroscopy confirmed that the complexes made from different fatty acids displayed similar V6 or V7 type polymorphs. Interestingly, small-angle X-ray scattering analysis revealed that α value became greater following increased carbon chain length of fatty acids, indicating the formation of a more ordered fractal structure in the aggregates. Changes in rheological parameters G' and G'' indicated that starch complexed with fatty acids was more likely to form a gel network, but difference among three CS-FAs complexes was significant, which might be contributed to their corresponding hydrophobicity and hydrophilicity raised from individual fatty acids. Importantly, digestion indicated that CS-LA complexes had the lowest hydrolysis degree, followed by the greatest RS content, indicating the importance of chain length of fatty acids for manipulating the fine structure and functionality of the complexes.

Effects of different extrusion temperatures on the physicochemical properties, edible quality and digestive attributes of multigrain reconstituted rice

Multigrain reconstituted rice, as a nutritious and convenient staple, holds considerable promise for the food industry. Furthermore, highland barley, corn, and other coarse cereals are distinguished by their low glycemic index (GI), rendering them effective in mitigating postprandial blood glucose levels, thereby underscoring their beneficial physiological impact. This study investigated the impact of extrusion temperature on the physicochemical properties, edible quality, and digestibility of multigrain reconstituted rice. The morphology revealed that starch particles that are not fully gelatinized in multigrain reconstituted rice are observed at an extrusion temperature range of 60 °C-90 °C. As the extrusion temperature increased, the degree of gelatinization (DG) increased, while the contents of water, protein, total starch, and amylopectin decreased substantially. Concurrently, the relative crystallinity, orderliness of starch, and heat absorption enthalpy (ΔH) decreased significantly, and water absorption (WAI) and water solubility (WSI) increased markedly. Regarding edible quality, sensory evaluation displayed an initial increase followed by a decrease. In terms of digestibility, the estimated glycemic index (eGI) increased from 61.10 to 70.81, and the GI increased from 60.41 to 75.33. In addition, the DG was significantly correlated with both eGI (r = 0.886**) and GI (r = 0.947**). The results indicated that the ideal extrusion temperature for multigrain reconstituted rice was 90 °C. The findings underscored the pivotal role of optimal extrusion temperatures in the production of multigrain reconstituted rice, which features low GI and high nutritional quality.

Effect of emulsified lipid and saponified lipid on the enzyme desizing of starch and its mechanism

To enhance the flexibility of starch film adhesion on yarns, sizing lipids (saponified lipid or emulsified lipid) must be added during the sizing process. However, different types of sizing lipids may have diverse combinations with starch to impact enzyme desizing. Therefore, this study investigated the effects of saponified lipid and emulsified lipid commonly used in warp sizing on the hydrolysis of starch. Additionally, the desizing efficiency and chain structure of desizing residues were analyzed. Experimental results demonstrated that the existence of saponified lipid or emulsified lipid led to a reduction in the degree of hydrolysis (1.1 % and 2.6 %, respectively) compared to the original corn starch. Notably, saponified lipid exhibited a relatively strong negative impact. Furthermore, the desizing efficiency decreased after adding emulsified lipid (1.2 %) or saponified lipid (2.9 %). Starch-lipid V-type complexes and physical hindrance could inhibit the enzyme desizing, resulting in a larger wavelength of maximum absorbance for desizing residues, along with higher molecular weight, z-average radius of gyration, and an increased proportion of long chains. The presence of saponified lipid significantly negatively influenced desizing, possibly due to the smaller particle size and propensity for complex formation with starch.

Preparation, structure, and in-vitro hypoglycemic potential of debranched millet starch-fatty acid composite resistant starch

Currently, the preparation methods and basic physicochemical properties of starch-FA complexes have been widely studied; however, no in-depth research on the regulatory mechanism of the digestive properties of debranched starch-unsaturated FA complexes has been conducted. Therefore, six fatty acids with different carbon chains and different degrees of unsaturation were complexed with de-branched millet starch in this research, using the microwave method. Microwave millet starch-linoleic acid complex (MPS-LOA) had the highest resistant starch (RS) content, and the structure and physicochemical properties of MPS-LOA were determined using various molecular techniques. The results indicate that MPS-LOA had a resistant starch (RS) content of 40.35% and the most notable fluorescence. The characteristic UV peaks of MPS-LOA were blue-shifted, and new IR peaks appeared. The crystalline structure changed to V-type crystals, the crystallinity increased, and the molecular weight decreased. The enthalpy and coagulability of MPS-LOA increased, and the swelling force decreased. Additionally, MPS-LOA showed enhanced α-glucosidase and α-amylase inhibition, and in-vitro hydrolysis kinetics analysis of MPS-LOA showed a hydrolysis index of 53.8 and an extended glycemic index (eGI)I of 54.6, indicating a low eGI food suitable for consumption by people with type II diabetes. These results provide a theoretical basis for the preparation of amylopectin- and starch-based foods with an anti-enzyme structure and a low glycemic index (GI).

Impacts of fatty acid type on binding state, fine structure, and in vitro digestion of debranched starch-fatty acid complexes with different debranching degrees

This study aimed to investigate the effects of fatty acid (FA) type on the binding state, fine structure, and digestibility of debranched maize starch (DMS)-FA complexes with different enzymatic debranching degrees. Maize starch was hydrolyzed by pullulanase for 1 h (DMS1h) and 6 h (DMS6h) and then complexed with seven types of FAs with varying chain lengths and unsaturation degrees, respectively. All the DMS-FA complexes showed V_6III-type and B-type crystals. Complex formation greatly increased the relative crystallinity of DMS, but significantly decreased its order degree of short-range structure (p < 0.05). Compared with unsaturated FAs, saturated FAs possessed stronger intermolecular interactions with DMS. DMS6h-FA complexes exhibited a markedly higher complexing degree (p < 0.05) than the corresponding DMS1h-FA complexes. The FA molecules in DMS1h-FA complexes were primarily physically trapped outside the amylose helices, whereas those in DMS6h-FA complexes were mainly weakly bound to the cavity of amylose helices. The resistant starch (RS) content and relative crystallinity of DMS-FA complexes considerably increased with increasing FA chain length. Furthermore, the highest RS content (38.90 %) and relative crystallinity (24.23 %) were observed in DMS6h-FA complexes. The FA unsaturation degree induced little effect on the RS content and long-range structural order of the complexes.

Preparation and characterization of debranched starches: Influence of botanical source and debranching time

The influence of botanical source (waxy corn, glutinous rice, tapioca and potato), either based on crystallization or morphology, and the debranching time (6-48 h) on the physicochemical properties of debranched starches (DBSs) were systematically investigated. The divergence of depolymerization among different botanical sources within same hydrolysis time suggested that the debranching treatment was not only depending on the molecular profile and crystalline structure, but also related with the granular size and morphology of native starches. Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) suggested that long-term debranching reaction produced DBSs with improved degree of crystallization and reduced iodine binding capacity. Simulated in-vitro digestion assay showed that the proportion of digestive fractions from different botanical originated DBSs differed greatly. Additionally, prolonging the debranching time yielded increased level of resistant starch. The study may provide guidance for exploring DBSs with various molecular weight to fulfill their tailored applications.

Influence of different kinds of fatty acids on the behavior, structure and digestibility of high amylose maize starch-fatty acid complexes

BACKGROUND

The formation of starch-lipid complexes is of interest to food processing and human nutrition. Fatty acid (FA) structure is important for the formation and structure of starch-FA complexes. However, there is limited research regarding the complexing behavior between amylose and different kinds of FAs, as well as the relationship between fine structures and digestibility of the formed complexes. This study aimed to investigate the behavior, fine structure, and digestibility of complexes formed between high amylose maize starch (HMS) and FA having various chain lengths and unsaturation degrees.

RESULTS

Complexes containing different FA structures showed V_6III -type crystals. Complexes containing 18-carbon unsaturated FAs displayed significantly higher complexing index (P < 0.05) than other complexes. Complexes containing 12-carbon FAs and 18-carbon FAs with one unsaturation degree showed a higher degree of structural order and resistant starch (RS) content than other complexes. The 12-carbon FAs exhibited a higher binding degree with helical cavity of amylose than other FAs. Additionally, 10-carbon and 18-carbon saturated FAs tended to combine with HMS outside amylose helices more than other FAs. Laser confocal micro-Raman imaging revealed that the physically embedded 10-carbon and 18-carbon saturated FAs showed heterogeneous distribution in complexes, and that the complexed 18-carbon FAs with one unsaturation degree exhibited homogeneous distribution.

CONCLUSION

The behavior, structural order and digestibility of complexes could be regulated by FA structure. The 12-carbon FAs and 18-carbon FAs with one unsaturation degree were more suitable for the production of HMS-FA complexes with higher structural order and RS content than other FAs. © 2022 Society of Chemical Industry.