Resistant Starch-rich Powders Prepared by Autoclaving of Native and Lintnerized Banana Starch: Partial Characterization

Effect of autoclave-cooling cycles combined pullulanase on the physicochemical and structural properties of resistant starch from black Tartary buckwheat

A starch-rich portion is produced as a by-product of black Tartary buckwheat processing. The effect of enzymatic combined with autoclaving-cooling cycles (one, two, or three times) on the physicochemical and structural properties of black Tartary buckwheat type 3 resistant starch (BRS) was evaluated. The autoclaving-cooling cycles enhanced solubility and reduced swelling, with the BRS content increasing from 14.12% to 25.18%. The high crystallinity of the BRS reflected a high molecular order. However, increasing the number of autoclaving-cooling cycles did not result in higher BRS content. The highest BRS yield in the autoclaved starch samples was 25.18% after double-autoclaving-cooling cycles. Furthermore, the autoclaving-cooling cycles altered the crystalline structure of black Tartary buckwheat, and the subsequent crystallinity changed from 36.33% to 42.05% to 38.27%. Fourier-transform infrared spectroscopy shows that the number of cycles results in more efficient double-helical packing within the crystalline lamella. Principal component analysis showed that the autoclaving-cooling cycle treatment leads to significant changes in the molecular structure of resistant starch (RS). These results indicated that autoclaving-cooling cycles might be a feasible way for producing RS from black Tartary buckwheat starch with better structural stability to expand their application range.

Physicochemical, Morphological, and Functional Properties of Starches Isolated from Avocado Seeds, a Potential Source for Resistant Starch

This study compared the physicochemical and functional properties of starches from eight cultivars of avocado seeds. Amylose content, morphology, crystalline structure, swelling power, solubility, thermal and pasting properties, and in vitro digestibility were investigated. The results revealed that the apparent amylose content of starches from avocado seeds varied with different varieties. Light microscopic and scanning electron microscopic examination demonstrated that the eight starches differed slightly in terms of morphology and granule size. The X-ray diffraction and Fourier transform infrared spectroscopy analyses showed that the crystal structure and chemical linkage of the avocado seed starches were similar. However, the pasting, water solubility, and thermal properties of the eight avocado seed starches differed. Importantly, all the starches had high resistant starch content (>60%), with the highest found in Hass seeds (77.83%). To conclude, starch from avocado seeds has a high potential for use in the production of resistant starch.

Verification of autoclaving-cooling treatment to increase the resistant starch contents in food starches based on meta-analysis result

Autoclaving-cooling is a common starch modification method to increase the resistant starch (RS) content. The effect of this method varies depending on the type of crop and treatment condition used. The objectives of this study were to verify the autoclaving-cooling treatment based on a meta-analysis result and to evaluate the physicochemical properties of modified starches. The meta-analysis study used 10 articles from a total of 1,293 that were retrieved using the PRISMA approach. Meta-analysis showed that the optimal treatments of autoclaving-cooling process that increase the RS content significantly, was in starch samples from the cereal group (corn, oats, rice) (SMD: 19.60; 95% CI: 9.56–29.64; p < 0.001), with water ratio 1:4 (SMD: 13.69; 95% CI: 5.50–21.87; p < 0.001), using two cycles of autoclaving-cooling (SMD: 16.33; 95% CI: 6.98–25.67; p < 0.001) and 30 min of autoclaving heating (SMD: 12.97; 95% CI: 1.97–23.97; p < 0.001) at 121°C (SMD: 12.18; 95% CI: 1.88–22.47; p < 0.001). Verification using corn flour and corn starch showed a significant increase in RS contents from 15.84 to 27.78% and from 15.27 to 32.53%, respectively, and a significant decrease in starch digestibility from 67.02 to 35.74% and from 76.15 to 28.09%, respectively. Treated sample also showed the pasting profile that was stable under heating and stirring.

Investigation of dual modification on physicochemical, morphological, thermal, pasting, and retrogradation characteristics of sago starch

The aim of this study was to evaluate the characteristics of dually modified sago starch by acid hydrolysis (AH)‐hydroxypropylation (HP). For this purpose, sago starch was modified with the combination by AH (5–20 h hydrolysis times) followed by HP (5%–25% ratio of propylene oxide) processes. The results showed that the dual modification of the sago starch structure didn't have a significant effect on the size of starch granules, and the granule size was in the range of 0.005–0.151 µm; however, the pasting properties and the glass transition temperature decreased significantly (p < .05). Increasing the level of propylene oxide from 5% to 25% caused a significant increase in the substitution degree (DS) and swelling ability of starches and reduced the syneresis, while with increasing acid hydrolysis time from 5 h to 20 h, starch swelling decreased and syneresis increased (p < .05). AH process at high hydrolysis times (20 h) increased the gelatinization temperatures and decreased retrogradation temperatures. Increasing the level of propylene oxide in both single and dual modification reduced the temperatures and enthalpy of gelatinization and retrogradation of sago starch. In summary, dually modified sago starch has a great potential to use in specific food products such as frozen dough or frozen bakery products.

Preparation and characterization of native and autoclaving-cooling treated Pinellia ternate starch and its impact on gut microbiota

The aim of this study was to investigate and compare the structural and physicochemical properties of native Banxia starch (BXS) and autoclaving-cooling treated Banxia starch (CTBXS) and its related impacts on production of short chain fatty acids (SCFAs) and human gut microbiota by in vitro fecal fermentation. BXS had semicircle to spherical granules, whereas CTBXS exhibited block-shape. According to XRD and TGA, BXS had a C-type crystalline pattern, while CTBXS had a B-type crystalline pattern. CTBXS had better thermal stability than BXS. In addition, BXS exhibited significantly higher solubility and swelling power than CTBXS, and CTBXS had higher content of SDS than BXS. Moreover, BXS and CTBXS could change the composition and abundance of gut microbiota, could also promote the production of SCFAs. This study is beneficial to well understand the in vitro digestion and fecal fermentation behaviors of BXS and CTBXS, and can be developed as a potential functional food with the aim of improving colonic health.

Thermal, morphological and structural characterization of a copolymer of starch and polyethylene

The objective of this paper was to perform a copolymerization between polyethylene and starch in order to obtain new environmentally friendly materials. The copolymer obtained was characterized thermally, morphologically and structurally, including its pasting profile. The starch-g-PE copolymer showed lower thermal stability compared to the control materials. FTIR analysis determined that the chemical bond signal between the starch and polyethylene in the copolymer overlaps with the native starch signals. The signal from this chemical bond was assigned by proton NMR spectroscopy at δ 4.45 ppm. X-ray studies of the copolymer showed a material with more amorphous characteristics compared to native starch. SEM analysis demonstrated the presence of cracks in the starch granules which favored the chemical interaction between the polymers. The pasting behavior of the copolymer was less pronounced compared to native starch. Therefore, the copolymerization of both polymers could be an alternative to recycle polyethylene and make biodegradable materials.

Effects of Lintnerization, Autoclaving, and Freeze-Thaw Treatments on Resistant Starch Formation and Functional Properties of Pathumthani 80 Rice Starch

The objective of this study was to assess the effects of lintnerization, autoclaving, lintnerization followed by autoclaving, and freeze thawing treatments on the production of resistant starch from Pathumthani 80 (RD 31) rice. The produced resistant starch was further evaluated for some important physicochemical properties including pasting properties, swelling behavior, digestibility, water holding capacity, and functional properties including glycemic index and antioxidant properties. The lintnerization treatment and autoclaving significantly (p ˂ 0.05) increased resistant starch content to 64% (w/w) and gave the lowest glycemic index (46.12%). The lintnerization followed by autoclaving treatment significantly increased the solubility and water holding capacity, reduced the swelling power, and disrupted the crystalline structure of the starch granules. The native rice starch with autoclave treatment exhibited the highest swelling power among the samples, while the acid hydrolyzed starch was followed by autoclave treatment showing the lowest swelling power (1 g/g) at 90 °C. Fourier transform infrared analysis revealed the modified structures and bonding of the starch materials with the shifting of C=O stretch. However, the antioxidant properties and pasting properties were observed to decrease with the lintnerization, autoclaving, and freeze-thawing treatment of the native starch. The highly resistant starch content and low glycemic index value of the autoclaved RD 31 starch indicates the potential of the resistant starch’s application for the formulation of functional foods targeting the diabetic population.

Effect of Non-Conventional Drying Methods on In Vitro Starch Digestibility Assessment of Cooked Potato Genotypes

Potatoes (Solanum tuberosum L.) are a good dietary source of carbohydrates in the form of digestible starch (DS) and resistant starch (RS). As increased RS content consumption can be associated with decreased chronic disease risk, breeding efforts have focused on identifying potato varieties with higher RS content, which requires high-throughput analysis of starch profiles. For this purpose, freeze drying of potatoes has been used but this approach leads to inaccurate RS values. The present study objective was to assess the starch content (RS, DS and total starch (TS)) of three cooked potato genotypes that were dried using freeze drying and innovative drying techniques (microwave vacuum drying, instant controlled pressure drop drying and conductive hydro-drying) relative to freshly cooked potato samples. Depending on the genotype, all drying methods showed one or more starch measures that were significantly different from freshly cooked values. The combination of ultrasound and infrared assisted conductive hydro-drying was the only method identified to be associated with accurate assessment of DS and TS content relative to fresh samples. The drying treatments were all generally associated with highly variable RS content relative to fresh controls. We conclude that freshly cooked samples must be used for selecting varieties with a high proportion of RS starch as drying of cooked potatoes leads to unreliable RS measurements.

Esterified plantain flour for the production of cookies rich in indigestible carbohydrates

The role of raw plantain flour (RPF) and its citric acid (CA)-esterified counterpart (EPF) on the carbohydrate nutritional properties of cookies was investigated. Cookies were elaborated with commercial wheat flour (CWF), RPF, EPF, or a CWF-EPF blend, and assessed for composition, starch digestibility, texture and sensory properties. EPF-cookie showed the lowest digestible starch (DS) content and estimated glycemic index (pGI) (25.0% and 59.3, respectively). Cookies made with CWF-EPF exhibited the highest indigestible fraction values attributed to the synergistic presence of the RS from EPF and the protein and non-starch polysaccharides from CWF. All RPF containing cookies exhibited lower hardness than CWF-cookie. Although the use of RPF decreased consumer's acceptability compared to CWF-cookie, the cookies with EPF showed sensory characteristics of 52-65% compared with the CWF-cookie (100%). This study shows CA esterification of plantain flour as a successful strategy to manufacture cookies with low DS and pGI.

Culled banana resistant starch-soy protein isolate conjugate based emulsion enriched with astaxanthin to enhance its stability

The conjugates of biomacromolecules such as proteins and polysaccharides have potential to stabilize the emulsion system and encapsulate valuable bioactive compounds for biofortification in food systems. In this study, native banana starch (NBS) was isolated from green culled banana and modified into resistant starch (type III) by lintnerization followed by autoclaving-cooling process, resulting in lintnerized-autoclaved banana starch (LABS). Soy protein isolate (SPI) was used for developing the polysaccharide-protein conjugates i.e. LABS-SPI conjugate and used as wall material to stabilize the oil-in-water emulsion system. LABS-SPI conjugate emulsions were subjected to in vitro digestion model and oxidative stability evaluation. Furthermore, the emulsion system was enriched with astaxanthin and evaluated for its stability. The chemical finger printing of LABS-SPI conjugates showed stretching in immine and enaminol group of Schiff's bases, the CN stretching of Amadori product. During in vitro digestion LABS-SPI conjugate emulsion showed that the presence of resistant starch had an influence on the droplet digestion process and significantly (p < 0.05) lower free fatty acid release compared to emulsions stabilized by SPI alone. LABS-SPI conjugate emulsion system demonstrated higher stability of astaxanthin at storage temperatures (6, 20 and 37 °C), and can be used for biofortification of food and pharmaceutical formulations.

Changes in resistant starch from two banana cultivars during postharvest storage

Banana resistant starch samples were extracted and isolated from two banana cultivars (Musa AAA group, Cavendish subgroup and Musa ABB group, Pisang Awak subgroup) at seven ripening stages during postharvest storage. The structures of the resistant starch samples were analysed by light microscopy, polarising microscopy, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy. Physicochemical properties (e.g., water-holding capacity, solubility, swelling power, transparency, starch-iodine absorption spectrum, and Brabender microviscoamylograph profile) were determined. The results revealed significant differences in microstructure and physicochemical characteristics among the banana resistant starch samples during different ripening stages. The results of this study provide valuable information for the potential applications of banana resistant starches.

Effects of autoclaving temperature and storing time on resistant starch formation and its functional and physicochemical properties

In this study effects of autoclaving temperature (140-145°C) and storing time (24, 48 and 72 h) on resistant starch (RS) formation from high amylose corn starch were investigated and functional and pasting properties of RS preparations were determined. High autoclaving temperature (145 °C) and long storing time (72 h) showed beneficial impacts on RS formation. Significant decreases were observed in all RVA viscosities of RS preparations as the autoclaving temperature increased. There was significant effect of storage time on all RVA parameters of RS preparations within each autoclaving temperature. The water binding values of RS preparations autoclaved at 145 °C were higher than those of the samples autoclaved at 140 °C. RS preparations had approximately 2-fold higher emulsion capacity values than the native starch. Thermal enthalpy (ΔH) values of RS preparations were lower than those of native starch. Autoclaving temperature and storing time had no effects on TO and TP.

The effect of three gums on the retrogradation of indica rice starch

Retrograded starch (RS(3)) was produced from indica rice starch with three kinds of gums (konjac glucomannan, KGM; carrageenan, CA, USA; and gellan, GA, USA) by autoclaving, respectively, and the effect of the gums on the retrogradation behavior of starch was estimated. The influences of polysaccharide concentration, sodium chloride concentration, autoclaving time, refrigerated time, and pH value on RS(3) formation were discussed. Except for sodium chloride's persistent restraint on RS(3), the others all forced RS(3) yields higher at first, but lowered it after the peak value. The influencing sequence of these impact factors was: sodium chloride concentration > polysaccharide concentration > autoclaving time > refrigerated time > pH value. The results also proved that in the three gums, KGM plays the most significant role in RS(3) changing. It was concluded that the incorporation of each of these three gums into starch, especially KGM, results in an increase or decrease of RS(3) under different conditions. This phenomenon could be taken into consideration when developing starchy food with appropriate amount of RS(3).