Amylopectin Research Articles

Silkworm cocoon-like nanocoatings for single-cell encapsulation of probiotics: Construction, mechanism and characterization

Single-cell encapsulation technology is an advanced method to protect probiotics from adverse environmental conditions by forming coating on the surface of individual probiotics. In this study, Lactiplantibacillus plantarum (L. plantarum) was used as model probiotic. Four polysaccharides, namely carboxymethyl chitosan (CMCS), chitooligosaccharide (COS), amylopectin (AP) and pectin (PE), as well as four proteins, namely gelatin (GE), whey protein isolate (WPI), ovalbumin (OVA) and soy protein isolate (SPI), were selected as the initial coating materials. The coated probiotics were prepared by single-cell encapsulation under pH 3.0–6.0 for the first time. The feasibility, mechanism and effect of these coatings were then explored. Results indicated that the positively charged materials were conducive to the formation of coating, and the optimal pH was 4.0. Silkworm cocoon-like coatings with a thickness of 100–150 nm on the surface of L. plantarum were observed. Subsequently, fourier transform infrared spectroscopy (FTIR) analysis showed that electrostatic interaction, hydrogen bonding and hydrophobic interaction were the main driving forces between coatings and L. plantarum. In addition, COS coating fostered the growth and reproduction of L. plantarum, while CMCS and OVA inhibited it. Finally, COS, WPI and GE coatings as barriers all improved the survival rate of L. plantarum under pasteurization, freeze-thaw cycle and storage conditions. Among them, COS as a marine oligosaccharide had the best protective effect on L. plantarum due to its excellent properties and the dense coating it formed. The results may provide more support for further development of nanocoated probiotics.

Optimization of Amylose to Amylopectin Ratio and Degree of Substitution in Quaternized Starch as a Tool to Improve Paper Strength

AbstractCationic starch serves as a prevalent wet‐end additive in the papermaking industry. Yet, the definitive effects of the ratio between the two principal components—amylose (AM) and amylopectin (AP)—and the degree of substitution (DS) on the mechanical strength enhancement of paper sheets remain incompletely understood. This study synthesizes a series of quaternized amylose (QAM) and quaternized amylopectin (QAP) with varying DS levels and blended these derivatives in diverse ratios. Subsequently, these mixtures are integrated into pulp suspensions to ascertain the DS and the AM‐to‐AP ratio that optimize paper strength. These results indicate that a QAM‐to‐QAP blend with a DS of 0.08 at a ratio of 2:8 yielded the most pronounced improvement in paper mechanical properties. This precise formulation significantly enhances tensile, burst, and tear strength indices, increasing by approximately 55.0%, 44.4%, and 78.4%, respectively, under the most favorable conditions and with an additive dosage of 1 wt.%. This investigation provides substantive and actionable knowledge for selecting starch additives in the wet‐end of papermaking, which can significantly augment the efficiency and efficacy of paper manufacturing processes.

Novel food-grade water-in-water emulsion fabricated by amylopectin and tara gum: Property evaluation and stability analysis

To surmount the limitation of the instability of the currently reported water-in-water (W/W) emulsions, novel W/W emulsionss were constructed using amylopectin (AMP) and tara gum (TG) as the phases, and differently shaped ovalbumin (OVA) particles were used as stabilizers to improve the stability of W/W emulsions. Experiments displayed that the conformation of OVA could be changed by heating treatment, thus forming fibrous or spherical OVA particles that had the potential to stabilize TG-in-AMP (TG/AMP) emulsions. The emulsions had the best stability when the pH was 4 and the concentration of OVA particles was 3 %. Moreover, since ovalbumin fibril (OVAF) had better adsorption at the water-water interface than ovalbumin sphere (OVAS), OVAF-stabilized TG/AMP emulsion (OF-TE) had a relatively denser interfacial layer and exhibited more satisfactory ionic stability and physical stability than OVAS-stabilized TG/AMP emulsion (OS-TE). The rheological results demonstrated that OVAF and OVAS had little effect on the viscosity of TG/AMP emulsions. In brief, OVAF was more effective in improving the stability of TG/AMP emulsions than OVAS, and OF-TE did not show phase separation for at least 5 days. This study may be of great significance in improving the stability of food-grade W/W emulsions.

Mechanism of maltogenic α-amylase modification on barley granular starches spanning the full range of amylose

Amylopectin (AP)-only (APBS), normal (NBS), and amylose (AM) only (AOBS) barley starches were selected here to investigate catalysis pattern of maltogenic α-amylase (MA) on hydrolyzing AP and AM granular starches. MA shortened starch side chains with degree of polymerization (DP) 11–30. MA-treated APBS exhibited porous granular structures and dramatically increased degree of branching (DB, 17–20 %), and reduced ordered degrees, suggesting high hydrolysis and transglycosylation activities of MA. MA-treated NBS showed less pronounced porous structures and slightly increased DB (2–4 %), indicating high hydrolysis but low transglycosylation activities. AOBS displayed minimal changes in DB (0.2–0.3 %) and starch structures, implying low hydrolysis and transglycosylation activities. Therefore, MA preferred to attack the AP molecules with abundant glucan substrates with DP 11–30, while AM restricted MA activity likely by creating ineffective binding sites and undergoing rapid reorganization. These findings deepened the understanding of the mechanisms of MA in modifying granular starches with varying AM content.

Structural, molecular, and physicochemical properties of starch in high-amylose durum wheat lines

There is growing interest in the development of high-amylose cereals such as wheat due to their functional properties and nutritional value in foods. The increase in amylose content is associated with significant changes in the physicochemical, molecular, and structural characteristics of wheat starch which could affect its processing quality. The present study aimed to analyze the physicochemical, molecular, and structural characteristics of high-amylose starch from three durum wheat near isogenic lines (NILs), each obtained using three different recurrent parents. Morphology, granule size distribution, pasting and thermal properties, X-ray diffraction, and structural features were determined. The NILs showed the highest amylose content (65.3 and 69.8%), granules with an elongated shape, size between the wild-type and the mutant, restricted swelling in the pasting profile, the highest average and final gelatinization temperature, and B-polymorphism. The starches from the NILs showed the highest molar mass of amylopectin (AP) (7.0–7.6 × 107 Da) and the lowest amylose (AM) (1.1–1.8 × 106 Da), an issue associated with the biosynthesis of both components. The study on the debranched sample by high-performance size-exclusion chromatography showed that the high-amylose starch had the highest content of long B2 and B3 chains of AP (23.9–26.6%), which was corroborated with the high-performance anion-exchange chromatography analysis where the chains with degree of polymerization >37 had the highest content (18.3–19.1%). The PC1 is highly associated with the MwAM and the AM fraction in the debranched starch analyzed by HPSEC. Characterizing high-amylose durum wheat starch provides information to determine the structure-function relationship and design strategies to produce crosses with structural characteristics of AM and AP for specific applications.

Mild alkali treatment alters structure and properties of maize starch: The potential role of alkali in starch chemical modification

Normal and waxy maize starches were treated with mild alkali treatment (pH 8.5, 9.9, 11.3) in two temperature-time combinations (25 °C for 1 h and 50 °C for 18 h) to investigate the effect on starch structure and properties. Mild alkali treatment partly removed the starch granule-associated proteins and lipids of normal (from 0.31 % to 0.24 % and from 0.77 % to 0.55 %, respectively) and waxy maize starches (from 0.22 % to 0.18 % and from 0.24 % to 0.15 %, respectively). Gelatinization enthalpy of waxy maize starch increased with alkali treatment from 16.20 J·g−1 to 21.95 J·g−1, indicating that amylopectin (AP) rearrangement and AP-AP double helices formation might occur. But amylose could inhibit these effects by restricting mobility of amylopectin, and no such changes occurred for normal maize starch. Alkali treatment decreased gelatinization temperature and increased peak and final viscosity. Alkali treatment decreased trough viscosity and increased setback of normal maize starch. The hydrothermal treatment promoted the effect of alkali, attributed to the more rapid molecular motion at higher temperature. Normal and waxy starches showed different changes after alkali treatment, indicating that amylose played an important role in controlling the effect of alkali and hydrothermal treatment, primarily as an obstructer of amylopectin rearrangement in mild alkali treatment.

Impact of Deformability and Rigidity of Starch Granules on Linear and Non-Linear Rheological Behavior of Waxy Rice Starch Gels and Applicability for Food End Uses.

The objective of this study was to investigate granule size and distribution and deformability of granules and their effect on the rheological properties of waxy starch gels. Native (granular) waxy rice gels (10%) were prepared, and their response in oscillatory shear was investigated in the linear and non-linear viscoelastic regime. The results show the gels were mainly composed of aggregated and deformed swollen granules. Significance of granule size and its distribution, deformability of granules, and the molecular characteristics of amylopectin (AP) on storage modulus of those gels was demonstrated. A low degree of deformability of granules, typical for small granules with a broad size distribution and small molecular size of AP with short external chains, resulted in rigid and brittle gels. Highly deformed granules and high AP leachates, however, yielded soft gels. It was found that the transition of elastic to plastic behavior in the non-linear regime (LAOS) was gradual when AP had long external chains, but an abrupt transition was observed with the gel with short exterior chains of AP. Differences in rheological properties of cohesive waxy starch gels appear to be mainly impacted by the varying degrees of granule deformability and rigidity, which is further attributed to a combination of factors, including granule size, particle size distribution, molecular size, the external chain length of amylopectin (AP), and lipid content. The significance of this study is that it will assist the food industry in selecting suitable waxy rice starches to gain desired textural properties of end products.

Insights into wheat-starch biosynthesis from two-dimensional macromolecular structure

Starch structure is often characterized by the chain-length distribution (CLD) of the linear molecules formed by breaking each branch-point. More information can be obtained by expanding into a second dimension: in the present case, the total undebranched-molecule size. This enables answers to questions unobtainable by considering only one variable. The questions considered here are: (i) are the events independent which control total size and CLD, and (ii) do ultra-long amylopectin (AP) chains exist (these chains cannot be distinguished from amylose chains using simple size separation). This was applied here to characterize the structures of one normal (RS01) wheat and two high-amylose (AM) mutant wheats (an SBEIIa knockout and an SBEIIa and SBEIIb knockout). Absolute ethanol was used to precipitate collected fractions, then size-exclusion chromatography for total molecular size and for the size of branches. The SBEIIa and SBEIIb mutations significantly increased AM and IC contents and chain length. The 2D plots indicated the presence of small but significant amounts of long-chain amylopectin, and the asymmetry of these plots shows that the corresponding mechanisms share some causal effects. These results could be used to develop plants producing improved starches, because different ranges of the chain-length distribution contribute independently to functional properties.

Investigating the evolution of the fine structure in cassava starch during growth and its correlation with gelatinization performance

The evolution of the starch fine structure during growth and its impact on the gelatinization behavior of cassava starch (CS) was investigated by isolating starch from South China 6068 (SC6068) cassava harvested from the 4th to 9th growth period. During growth, the short-range ordered structure, crystallinity as well as particle size distribution of starch were increased. Meanwhile, the starch molecular size and amylopectin (AP) proportion increased, while the proportion of amylose (AM) exhibited a decreasing tendency. The chains of short-AM (X ~ 100–1000) were mainly significantly reduced, whereas the short and medium-AP chains (X ~ 6–24) had the most increment in AP. The solubility, thermal stability, shear resistance, and retrogradation resistance of starch were enhanced after gelatinized under the influence of the results mentioned above. This study presented a deeper insight into the variation of starch fine structure during growth and its influence on gelatinization behavior, which would provide a theoretical basis for starch industrial applications.

Development of a Sustainable Biobased Flame-Retardant Microcapsule and Its Flame-Retarding Mechanism on Asphalt Combustion.

To develop an efficient, sustainable, and eco-friendly biobased flame-retardant microcapsule suitable for the working environments of tunnel asphalt pavement and reveal its flame-retarding mechanism on asphalt combustion, microencapsulated amylopectin (MAMP) was first prepared using an in situ polymerization method. Changes in the basic properties of amylopectin (AMP) and its compatibility with asphalt after microencapsulation were studied. Then, the flame retarding efficiency and improvement effects of MAMP on the flame retardancy of asphalt were investigated. Results show that melamine formaldehyde (MF) resin is evenly coated on the AMP surface without changing the chemical composition of AMP, increasing the thermal stability of AMP and the compatibility between AMP and asphalt. MAMP reacts with ammonium polyphosphate (APP) to release a number of incombustible gases to delay asphalt combustion at early stages and subsequently dehydrates to form a stable starch-based charring layer to suppress heat and mass transfer during asphalt combustion, improving the fire safety of asphalt materials. The added 3% MAMP can reduce the total enthalpy value of all exothermic peaks of the 10% APP-modified asphalt by 43.6%. As a carbonization agent, MAMP produces a charring layer with higher heat capacity during asphalt combustion, exerting an excellent inhibition effect on heat release. This study provides a reference for the application of biobased materials in flame-retarded asphalt pavements.

Effect of solution on starch structure: New separation approach of amylopectin fraction from gelatinized native corn starch

The complete dissolution of starch without degradation are necessary prerequisites for starch fractionation to obtain amylose or amylopectin (AP). With the recent, continuous progress in finding efficient and eco-friendly starch-dissolving solutions, applying new solvents for starch fractionation is important. In this study, the effects of dimethyl sulfoxide (DMSO), NaOH, and CaCl2 solutions on starch structure and AP product parameters during starch fractionation were compared with respect to the starch deconstruction effect. This study proved that the CaCl2 solution could effectively dissolve corn starch (50 °C, solubility of 98.96 %), and promote the regeneration of starch into uniform and fine particles. Furthermore, the three solvents (DMSO, NaOH, and CaCl2) changed the crystal structure of corn starch, but they were all non-derivatizing solvents. The effect of the CaCl2 solution on the molecular structure of corn starch was the least significant of the three solvents. Finally, the extraction rate of AP from the CaCl2 solution reached 69.45 %. In conclusion, this study presents a novel and effective method for AP extraction.

Role of Varieties of Starch in the Development of Edible Films—A Review

AbstractStarch, a stored form of energy in plants, plays an important role in the human diet as it is a vital source of carbohydrate. The classification of starch based on its botanical origin as cereal starch, tuber starch, and millet starch gives a new dimension to starch classification. The starches generally have an amylose (AM) content of 20–30%, amylopectin (AP) of 70–80% and gelatinization temperature of 60–95°C. Conventionally, starch is used in the food industry as a thickening agent and flavor enhancer in soups, sauces, bakery, and confectionery products. But, the less explored area is its utilization in the manufacture of edible films. Starch, due to its plasticizing effect, gelatinization, and pasting property produces film with desirable tensile strength (TS), elongation at break (EAB), and water vapor permeability (WVP). Starch films are not only biodegradable and renewable, but also possess excellent barrier properties. These films produced by wet and dry processing techniques can be used to package confectioneries, meat, sea foods, fruits, and vegetables. In the recent times, superhydrophobic, active, and agro‐waste based edible films have gained industrial importance.

Specific Modification of Granular Potato Starch by Means of Partial Debranching Using Pullulanase

AbstractNative potato starch (PS‐N) is enzymatically modified in the granular state using pullulanase (PUL) for the purpose of a specific partial molecular degradation of the polymers. The PUL compound is added to the aqueous starch suspension (40%, w/w) and processed. The process parameters are varied systematically (enzyme dosage [ENZ] 4/20 mL; pH of the suspension [pH 4.7/7.3]; hydrolysis temperature [TEMP] 40/50 °C, and hydrolysis duration [TIME] 20/120 min) and a new‐developed heat‐induced enzyme inactivation approach (storage of the partially dewatered moist starch for 120 min at 100 °C) is intended to terminate the hydrolysis. Morphological (LM, SEM, and CLSM) and thermal characterization (DSC) of the starch products indicate a partial damage of the granules and a partial loss of the semicrystalline structure owing to the heat treatment, which is confirmed by XRD. The molecular properties (SEC‐MALS‐DRI) are mainly controlled by the factors ENZ, pH, and TEMP, but the intended degradation of the amylopectin (AP) by cleavage of the α‐1,6‐linkages (debranching) is accompanied by a molecular degradation of the amylose (AM) fraction. However, both specificity of the hydrolysis and achievable gel strength are remarkably improved compared to acid‐thinned products.

Differences in rice component distribution across layers and their relationship with taste.

Rice taste is closely associated with endosperm composition, which varies among different rice layers. Although clarifying the relationship between this difference and nutritional taste can guide rice breeding and cultivation practices, research on this topic is limited. Here, typical rice varieties having excellent and poor taste characteristics were selected to analyze the distribution characteristics and differences of their components. The varieties with excellent taste exhibited lower apparent amylose content (AAC) and protein content (PC), lesser short-chain (Fa) and long-chain (Fb3 ) amylopectin (AP) and more medium-chain (Fb1+2 ) AP, higher long-to-short chain ratio (Fa:Fb3 ), and higher nitrogen (N), magnesium (Mg) and calcium (Ca) content in layer 1 (L1) than the varieties with poor taste. Layer 2 (L2) played a key role in AAC and PC regulation in the varieties with excellent taste by reducing AAC and appropriately increasing PC, consequently improving rice taste. AP structure in layer 3 (L3) substantially affected the taste of the two types of varieties. The mineral content was the highest in L1, and increased potassium (K), Ca, and Mg content improved taste in all varieties. AAC in each layer contributes to rice taste. PC and minerals primarily act on L1 and L2, whereas AP acts on L2 and L3. Therefore, the endosperm formation process should be exploited for improving rice taste. Furthermore, key resources and cultivation should be identified and regulated, respectively, to improve rice taste. © 2023 Society of Chemical Industry.

An Ultrahighly Stretchable and Recyclable Starch-Based Gel with MultipleFunctions.

With the development of various gel-based flexible sensors, novel gels with multiple integrated and efficient properties, particularly recyclability, have been developed. Herein, a starch-based ADM (amylopectin (AP)-poly(3-[dimethyl-[2-(2-methylprop-2- enoyloxy)ethyl]azaniumyl]propane-1-sulfonate) (PDMAPS)-MXene) gel is prepared by a facile "cooking" strategy accompanying the gelatinization of AP and polymerization reaction of zwitterionic monomers. Reversible crosslinking in the gel occurs through hydrogen bonding and electrostatic interactions. The ADM gel exhibits high stretchability (≈2700%, after one month), swift self-healing performance, self-adhesive properties, favorable freezing resistance, and satisfactory moisturizing properties (≥30days). Interestingly, the ADM gel can be recycled and reused by a "kneading" method and "dissolution-dialysis" process, respectively. Furthermore, the ADM gel can be assembled as a strain sensor with a broad working strain range (≈800%) and quick response time (response time 211ms and recovery time 253ms, under 10% strain) to detect various macro- and micro-human-motions, even under harsh conditions such as pronunciation and handwriting. The ADM gel can also be used as a humidity sensor to investigate humidity and human respiratory status, suggesting its practical application in personal health management. This study provides a novel strategy for the preparation of high-performance recycled gels and flexible sensors.

Effects of Pedoclimate and Agronomical Management on Yield and Quality of Common Wheat Varieties (Triticum aestivum L.) in Afghanistan

The lower common wheat productivity and quality are major constraints in Afghanistan. The objectives of this study were to (1) quantify the effect of soil and climatic parameters on the yield and quality of common wheat and (2) investigate the response of different wheat varieties to different N and P fertilization rates, to improve the yield and quality of common wheat. Three wheat varieties (DLN7, ZRDN, and KBL13), three phosphorus levels (PL) at 60, 90, and 120 kg P2O5 ha−1, and three nitrogen ratios (NP) at 1:1, 1.25:1, and 1.5:1, respectively, in four locations (L), were evaluated. The higher average grain yield (GY), straw yield (SY), and starch yield (STY) were obtained with DLN7, followed by KBL13 and ZRDN, for all locations. As PL increased, GY, SY, protein yield (PY), and STY significantly increased in all locations. The PL significantly affected protein content (PC), gluten content (GC), and dough strength (W). The NP significantly improved PC, GC, and PY. Starch (ST), STY, and amylopectin (AP) increased significantly with increasing PL. The amylose to AP ratio increased significantly with increasing NP ratios. The findings show that at NP1/PL120, GY, SY, ST, and AP improved significantly, while at NP1.5:1/PL120, PC and GC improved significantly.

Unveiling the Impact of Different Nitrogen Fertilizer Levels on Rice’s Eating Quality through Metabolite Evaluation

We investigated the variations in metabolites associated with the quality of rice consumption when exposed to varying nitrogen fertilizer levels, as well as the regulatory role of pivotal metabolites within metabolic pathways. This research employed Hongyang 5 as the subject of experimentation, examining the metabolites of Hongyang 5 at three different nitrogen levels using non-targeted metabonomic analysis. The findings indicated that the overall assessment of the eating quality/palatability (CEQ) and amylose contents (AC) of Low nitrogen (D1: 180 kg·ha−1) was notably greater than that of Medium nitrogen (D2: 270 kg·ha−1) and High nitrogen (D3: 315 kg·ha−1). Conversely, the amylopectin (APC), total starch (SC), and protein contents (AP) of D1 were remarkably lower than those observed in D2 and D3. The starch debranching enzyme (DBE) and granule-bound starch synthetase (GBSS) of D1 were remarkably higher than those of D2 and D3. The soluble starch synthase (SSS) of D1 was the lowest. The ADP-glucose pyro-phosphorylase (AGP) and starch branching enzyme (SBE) of D3 were remarkably higher than that of D1 and D2. We identified 76 differential metabolites (DMs) between D1 and D2 (20 up-regulated and 56 down-regulated). A total of 88 DMs were identified between D3 and D1 (42 up-regulated and 46 down-regulated). A total of 57 DMs were identified between D3 and D2. Most of the DMs related to rice-eating quality were involved in the lipid metabolic pathway and amino acid metabolic pathway. The essential metabolites within the metabolic pathway are classified as lipid metabolites and are (13(S)-hydroperoxylinolenic acid, PGB2, 3-phosphocholine, 7-epijasmonic acid, 20-carboxyleukotriene B4 and 11-dehydro-thromboxane B2), amino acid metabolites (4-guanidinobutanoic acid, (3R, 5S)-1-pyrroline-3-hydroxy-5-carboxylic acid, citric acid, (S)-2-Acetolactate, L-glutamine, L-2, 4-aminobutyric acid and putrescine). These key metabolites may be affected by nitrogen fertilizer conditions and play critical regulatory roles in the metabolic pathway, resulting in differences in rice eating quality.

Effects of different starch structures on energy metabolism in pigs

BackgroundStarch is a major component of carbohydrates and a major energy source for monogastric animals. Starch is composed of amylose and amylopectin and has different physiological functions due to its different structure. It has been shown that the energy supply efficiency of amylose is lower than that of amylopectin. However, there are few studies on the effect of starch structure on the available energy of pigs. The purpose of this study was to measure the effect of different structures of starch in the diet on the net energy (NE) of pigs using a comparative slaughter method and to establish a prediction equation to estimate the NE of starch with different structures. Fifty-six barrows (initial BW 10.18 ± 0.11 kg) were used, and they were housed and fed individually. Pigs were divided into 7 treatments, with 8 replicates for each treatment and 1 pig for each replicate. One of the treatments was randomly selected as the initial slaughter group (ISG). Pigs in the remaining treatments were assigned to 6 diets, fed with basic diet and semi-pure diets with amylose/amylopectin ratio (AR) of 3.09, 1.47, 0.25, 0.15 and 0.12, respectively. The experiment lasted for 28 d.ResultsResults showed that compared with the high amylose (AM) groups (AR 3.09 and 1.47), the high amylopectin (AP) group (AR 0.15) significantly increased the final BW, average daily weight gain and average daily feed intake of pigs (P < 0.05), but the F:G of the AM group was lower (P < 0.01). In addition, AR 0.15 and 0.12 groups have higher (P < 0.01) nutrient digestibility of dry matter, crude protein, gross energy and crude ash. Meanwhile, compared with other groups, AR 0.15 group has a higher (P < 0.05) NE intake and energy retention (RE). The regressive equation for predicting with starch structures was established as RE = 1,235.243 − 48.298AM/AP (R2 = 0.657, P = 0.05).ConclusionsIn conclusion, NE intake and RE of pigs augmented with the increase of dietary amylopectin content, indicating that diets high in amylopectin were more conducive to promoting the growth of pigs in the late conservation period.

Colorimetric pH indicators based on well-defined amylose and amylopectin matrices enriched with anthocyanins from red cabbage

This study aimed to prepare a novel colorimetric indicator film from virtually pure (99 %) amylose (AM) and anthocyanins extracted from red cabbage (RCA). The AM used was a unique engineered bulk material extracted from transgenic barley grains. Films produced by solution casting were compared to normal barely starch (NB) and pure barley amylopectin (AP), with amylose contents of 30 % and 0 %, respectively. The pH-indicator films were produced by incorporation of RCA into the different starch support matrices with different amylose contents. Barrier, thermal, and mechanical properties, photo degradation stability, and release behavior data revealed that RCA interact differently through the glucan matrices. Microstructural observations showed that RCA were evenly dispersed in the glucan matrix, and AM+RCA indicator films showed high UV-barrier and mechanical performance over normal starch. FTIR revealed that RCA was properly affected by the AM matrix. Moreover, the AM+RCA films showed sensitive color changes in the pH range (2–11) and a predominant Fickian diffusion release mechanism for RCA. This study provides for the first time data regarding AM films with RCA and their promising potential for application as support matrices in responsive food and other industrial biodegradable packaging materials.

Structures and digestibility of B-type high-amylose rice starches compared with A-type high-amylose rice starches

The starch structures and digestibility of starches prepared from newly developed Korean high amylose rice varieties were investigated. Amylose (AM) contents of Goami, Shingil, Goami 2, and Dodam starches were 25.56, 30.34, 36.33, and 45.78%, respectively. The Goami and Shingil starches were A-type crystallinity, while the Goami 2 and Dodam starches were B-type crystallinity. The molecular weights of AM were lower in the B-type starches (1.64 × 105 and 1.88 × 105) than in the A-type starches (3.88 × 105 and 3.00 × 105). The average chain length (CL) and longer branch CL (DP ≥ 25) of amylopectin (AP) were higher in B-type rice starches than in A-type rice starches. The ratio of 1045/1022 cm-1 and relative crystallinity were lower in the B-type rice starches. These results show that B-type starches have a higher AM content (>35%), gelatinization temperature, resistance to digestibility, and longer branch CL of AP, but a lower AM molecular weight than A-type starches.