•Cyanidin-3-(6″-malonylglucoside) was the major anthocyanin in blue maize.•Anthocyanins modified nutritional in vitro starch fractions.•Anthocyanins contributed to RS formation.•Blue maize products ...can present low starch digestibility.
The purpose of this study was to evaluate the effect of blue maize extracts obtained by acid-methanol treatment on the nutritional in vitro starch fractions such as: rapidly digestive starch (RDS), slowly digestive starch (SDS) and resistant starch (RS) of native and gelatinized commercial maize starch. Chromatographic analysis (HPLC-DAD/ESI-MS) of blue maize extracts showed the presence of seven anthocyanins, where cyanidin-3-(6″-malonylglucoside) was the main. Blue maize extracts modified nutritional in vitro starch fractions (decrease of RDS) while RS content increased (1.17 and 2.02 times for native and gelatinized commercial maize starch, respectively) when anthocyanins extracts were added to starch up to 75% (starch weight). This preliminary observation provides the basis for further suitability evaluation of blue maize extract as natural starch-modifier by the possible anthocyanins-starch interaction. Anthocyanin extracts can be a suitable to produce functional foods with higher RS content with potential human health benefits.
The objective of the work was to evaluate OSA-esterified taro starch as wall material to encapsulate avocado oil as lipophilic bioactive compounds, using spray drying for encapsulation. It was found ...that OSA-esterification decreased the amylose content (8.93–6.13%), %C (33.29–31.88%), and thermal properties of gelatinization (Tp: 86.1 to 80.7 °C, and △H: 8.4 to 7.9 J g−1). Besides, OSA-esterification did not modify the diffraction pattern (Type A). The OSA-starch granules did not show surface alterations, while showing a monomodal particle diameter distribution. However, the particle diameter increased from 2.8 to 3.3 μm after modification. The emulsions of OSA-starch (350 and 400 mg starch. mL−1 oil) showed greater stability against coalescence than those obtained with unmodified starch. Encapsulates with native and OSA-starches showed differences in diameter, shape and presence of pores. Likewise, the esterification reduces the diameter distribution in the microcapsules (15.1–13.1 μm). The vegetable oil was located internally and superficially in the cavities and intraparticle area of the microcapsules. Encapsulation efficiency was increased by modification with OSA from 23.63 to 40.0% and the value of peroxides decreased during storage. The results demonstrated that malanga OSA-starch can be considered as wall material for protection of hydrophobic substance.
•Encapsulates with OSA taro starch showed reduction in diameter compare with its native counterpart.•Encapsulation efficiency of avocado oil increased with OSA taro starch.•Avocado oil was present in the internally and superficially cavities and interparticle area.•The core material showed low rancidity during storage.
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.
► Banana starch was more resistant to acetylation in relation to normal corn starch. ► Restricted swelling was present in acetylated banana starch. ► Degree substitution of acetylated starches ...influenced the rheological parameters. ► Native banana starch contains high amount of long chains of amylopectin in relation to normal corn starch.
The effect of iodine concentration on the acetylation of starches with low and moderate degree of substitution (DS<0.5) and its impact on the physicochemical feature and structural features was evaluated. The acetylated starches were prepared with 0.03mol anhydroglucose unit, 0.12mol of anhydride acetic, and 0.6, 0.9 or 1.4mM of molecular iodine as catalyst in a sealed Teflon vessel using microwave heating (600W/2min). Pasting profile and rheological properties were obtained under steady flow; dynamic oscillatory test was used. Structural features were obtained by HPSEC-RI. In acetylated starches, DS and acetyl groups increased when the iodine concentration increased, corn starch showed higher values than banana starch. The viscosity of acetylated starches decreased relative to unmodified starches while, acetylated corn starch had lower value than acetylated banana starch. In the flow curves, a non-Newtonian pattern (shear-thinning) was shown in the pastes of native and modified starches. Storage modulus (G’) and loss modulus (G”) showed low dependence on frequency (G’αω0.1; G”αω0.2) on frequency sweep test, which is characteristic of a viscoelastic gel. Debranched native banana and corn starches presented trimodal chain-length distribution. The pattern was maintained in the acetylated starches, but with different level of short and long chains. The structural differences in native and acetylated samples explain the rheological characteristics in both starches.
Taro starch was isolated from Mexican variety and its morphological, physicochemical, and molecular characteristics were evaluated. Yield starch (in dry basis) was 81%, and this starch had low AM ...content (2.5%). Taro starch granules showed a mixture of shapes with sizes between 1 and 5 µm. Taro starch presented an A-type XRD pattern with a crystallinity level of 38.26%. Solubility and water retention capacity did not change in the temperature range of 50-70°C and thereafter they increased as temperature increased too. Taro starch showed high peak viscosity due to its high AP content. The peak temperature of gelatinization of taro starch was 80.6°C with an enthalpy value of 10.6 J/g, with low retrogradation rate due to its low AM content. Weight-average molar mass (Mw) and gyration radius (Rz) of taro starch were 1.21 ± 0.8 × 10⁹ g/mol and 424 ± 70 nm, respectively. Taro tuber could be an alternative for starch isolation with functional and physicochemical characteristics for food and non-food applications.
Cross-linked starches have increased their importance due to their applications such as adsorbents of heavy metals. In this work the effect the reagent used in the chemical modification of banana ...starch and its impact on some morphological, physicochemical and functional characteristics was evaluated. The reagent used in the cross-linked of starch decreased the fat and protein content, whereas ash level were higher. The morphology of the granules, observed by scanning electron microscopy, was more affected when a blend of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) and epichlorohydrin (EPI) were used in the modification. The cross-linked starches presented a bimodal distribution and the effect was more conspicuous in those starches modified with STMP/STPP and EPI. The swelling value (60
°C) increased with the cross-linking and the highest value was obtained in those starches modified with STMP/STPP and EPI. However, at higher temperatures the swelling values of cross-linked starches with STMP/STPP and EPI decreased as temperature increased (80
°C), and there after the value was constant. The cross-linked starches with STMP/STPP and EPI showed the lowest solubility values. The cross-linked starch with POCl
3 (phosphorous oxychloride) showed a slight decrease in the onset and peak temperatures compared with its native counterpart, but those modified with STMP/STPP and EPI presented an increase in the three transition temperatures, but a decrease in enthalpy value. The results obtained can be used to determine the type of reagent used for cross-linked in order to obtain a starch with specific characteristics.
In diverse industries, the starch of different botanical sources is widely used due to its functionality. The objective was to evaluate thermal properties, rheological behavior, particle size ...distribution and structural characteristics of starch isolated from pearled and whole barley. Commercial corn starch was used for comparison. Whole barley starch (WBS) and pearled barley starch (PBS) had average gelatinization temperatures of 61.3 and 61.6
°C, and enthalpy values of 9.19 and 8.54
J/g, respectively. The stored samples for 7
days presented a phase transition temperatures of 49.9 and 51.8
°C, and enthalpy value of 1.9 and 1.7
J/g, for WBS and PBS, respectively. At the longest storage time (14
days) the temperature of the phase transition was similar and an increase was showed in the enthalpy value for WBS (2.3
J/g) and PBS (2.4
J/g). The viscoelastic behavior of pastes at 90
°C and gels at 25
°C were characterized by
G′
>
G″ and no statistical difference was found between both starches. The granule size distribution of PBS and WBS showed a bimodal pattern. The pearled process of barley did not affect significantly some characteristics of its starch.
Banana and maize starches were acetylated with acetic anhydride in the presence of different levels of catalytic agent (iodine) using microwave heating. Degree substitution, he Fourier transforms ...infrared (FT-IR) spectra, the morphological properties, the gelatinization and retrogradation characteristics, the pasting property and X-ray diffraction pattern were evaluated. The FT-IR study showed that acetylation was produced in both starches, a strong absorption band at 1740 cm⁻¹, and this signal rose when the concentration of iodine increased; this pattern was corroborated with degree substitution of both starches. SEM revealed more exo-corrosion and fusion in acetylated maize starch granules. Acetylated banana starch had higher crystallinity level than maize starch, and the crystallinity level decreased when the catalyst concentration increased. Similar pattern was show for the average temperature and enthalpy of gelatinization. In general, the acetylation retards the starch retrogradation, but at longer storage time this effect was minimized. Difference in the retrogradation level was found between both starches. Using microwave heating and different iodine concentrations as catalyst is possible produce acetylation of starch with specific physicochemical characteristics.
Starch isolated from unripe bananas was oxidized under different conditions and the physicochemical properties of the oxidized banana starches were characterized. It was found that pH was the ...dominating factor in the formation of carboxyl groups. Higher yields of carboxyl groups were found when oxidized starch was prepared at pH 11.5 as compared with 7.5. Longer reaction time also produced a higher carboxyl value. Maltese crosses were still visible in the polarized light micrographs of oxidized banana starch, indicating that the ordered arrangement of starch molecules was not altered. The diffraction pattern of both native and oxidized banana starches was a mixture of A- and B-types. No difference was noted in the absorbance ratio as measured by infrared spectroscopy between the oxidized banana starches at both pHs. The onset and peak gelatinization temperatures increased and gelatinization range decreased with increasing pH during the oxidation. For pasting properties, viscosity significantly decreased during heating and cooling with the most drastic reduction noted for the sample oxidized at pH 11.5. All starches showed a non-Newtonian shear-thinning behavior. The oxidation reaction that incorporated chemical groups produced a softer system in banana starch due to the possible incorporation of more water molecules in its structure.
ABSTRACT
Structural characteristics of starches have been important to determine their physicochemical and functional properties. Solubilization procedures were tested to find a higher solubilization ...percentage and thereafter to study the structural characteristics of amylose and amylopectin. Size‐exclusion chromatography with refractive index (SEC‐RI) system using a pullulan standard curve was tested to study the amylose molar mass. Also, a microbatch system using a MALLS detector was used to determine the molar mass and gyration radius of starch and amylopectin. Microwave heating produced higher solubility percentages than autoclaving, and there was a difference between both starches. The sample solubilized with microwave heating presented higher molar mass and gyration radius values than autoclave samples, showing that this process for structural studies provided information representative of the initial starch sample. When starch components were separated, amylose showed lower purity than amylopectin. Lower purity was obtained for amylose separated from barley starch, but no difference was obtained for purity of amylopectin separated from both starches. Barley amylopectin had a higher solubility percentage than maize amylopectin. Molar mass of barley amylose was 1.03 × 105 g/mol and for maize of 2.25 × 105 g/mol. Molar mass values of amylopectin separated from both starches were lower than the starch counterparts, although the same solubilization procedure (microwave heating) was used. The difference might be due to depolymerization during separation of starch components.
