Characteristics of starch from different bean genotypes and its effect on biodegradable films

Hydrogel properties of non-conventional starches from guabiju, pinhão, and uvaia seeds

The physicochemical properties of starch vary depending on the botanical sources, thereby influencing the gelatinisation/retrogradation properties and subsequently affecting the hydrogels characteristics. This study aimed to assess the influence of botanical sources influence on starch and hydrogel properties using non-conventional starch derived from guabiju, pinhão, and uvaia seeds. Hydrogels were prepared by starch gelatinisation followed by 6 h ageing period at room temperature (20 ± 2 °C) and subjected to five freeze-thaw cycles. Pinhão starch exhibited a higher viscosity peak and breakdown, along with a lower final viscosity and setback, compared to guabiju and uvaia starches. The significantly different pasting properties influenced the porous microstructure, water absorption (p-value: 0.01), and resistance of the hydrogels (p-value: 0.01). The guabiju starch hydrogels showed a uniform pore structure without cavities, whereas pinhão and uvaia starch hydrogels exhibited agglomerated and spongy pore structures. Furthermore, the guabiju starch hydrogel demonstrated the lowest water absorption (4.56 g/g) and the highest compression resistance (1448.50 g) among all the studied starch hydrogels. In contrast, the pinhão starch hydrogel showed the highest water absorption (7.43 g/; p-value: 0.01) among all studied starch hydrogels. The hardness of uvaia starch hydrogel did not differ significantly from the guabiju and pinhão starch hydrogel. The different non-conventional starches reveal important variations in the hydrogels characteristics. This provides insights into how amylose and amylopectin interact and present alternatives for using these unique starch-based hydrogels in diverse applications.

Chachafruto starch: Physicochemical characterization, film-forming properties, and 3D printability

This work aimed to characterize the physicochemical, film-forming properties, and 3D printability of a nonconventional starch from chachafruto. The chachafruto native starch (CHS) presented an excellent extraction yield (10 % db) and purity (99 % db), along with an oval and round morphology, a smooth surface with few defects, and a mean diameter of 15.4 μm. The typical B-type diffraction pattern was observed in the CHS with a crystallinity of 17.4 %. The starch presented a paste temperature of 66.1 °C, an enthalpy of 11.5 J g-1, and a final viscosity of 596 Brabender Units. The thermal analysis demonstrated good thermal stability. The evaluated film presented a reduction in crystallinity (8.18 %) to the CHS, which generated a good elasticity in the material. Likewise, it presented a continuous structure without cracks, providing good barrier properties (2.3 × 10-9 g∙m-1∙s-1∙Pa-1) and high transparency. Meanwhile, 3D prints prepared with CHS showed good textural properties and high consistency. The morphological analysis showed that the prints generated organized cell structures. However, high concentrations of CHS were not efficient in obtaining 3D prints. The results of this work demonstrate the tremendous industrial potential of chachafruto as an unconventional source of starch and some alternative uses for adding value to the crop.

Non-conventional starches isolated from agronomic-improved beans (Phaseolus vulgaris L.): a study of their structure and physicochemical properties

BACKGROUND

Non-conventional starch sources are promising alternative food ingredients. Different bean varieties with agronomic improvements are constantly being developed and cultivated in the Northwestern Argentinean region (NOA) to increase yields and obtain high-quality seeds. However, the main attributes of their starches have not been studied. In this work, starches from four agronomic-improved bean cultivars were isolated and their structure and physicochemical properties were evaluated.

RESULTS

High-purity starches were obtained, as shown by their low protein and ash content. Starch granules presented smooth surfaces with spherical to oval shapes, with a marked 'Maltese cross' and heterogeneous sizes. Their amylose content revealed a mean value of 318 g kg^-1 and all presented resistant > slowly digestible > rapidly digestible starch fractions. Their Fourier transform infrared spectra were similar and X-ray diffraction analysis showed a C_A -type pattern in all cases despite their different sources. Among thermal properties, Escarlata starch showed the lowest gelatinization peak temperature (69.5 °C) and Anahí starch the highest (71.3 °C). Starch pasting temperature varied from 74.6 to 76.9 °C, whereas peak viscosity and final viscosity showed a similar tendency, with Leales B30 < Anahí < Escarlata < Cegro 99/11-2 and Leales B30 < Anahí = Escarlata < Cegro 99/11-2, respectively.

CONCLUSION

This study provides the basis for a better understanding of the characteristics of agronomic-improved NOA bean starches, enabling their use in product formulation as an alternative to starches from conventional sources. © 2023 Society of Chemical Industry.

Modification of Pea Starch Digestibility through the Complexation with Gallic Acid via High-Pressure Homogenization

Pea starch and some legume starches are the side streams of plant-based protein production. Structural modification toward moderate digestibility and desirable functionality is a way to increase the economic values of these side-stream starches. We applied an innovative and sustainable technique, high-pressure homogenization, to alter pea starch structure, which resulted in a high level of complexation with the small phenolic acid molecule, gallic acid, to alter starch digestibility. This study showed a great level of disruption of the compact starch structure represented by the decrease in gelatinization temperature, enthalpy change, and relative crystallinity. The addition of a high concentration (10%) of gallic acid contributed to a typical V-type X-ray diffractometry pattern. Data demonstrated a significant decrease (~23%) in the susceptibility to α-amylase and an increase in resistant starch (~13%). In addition, starch functionality was improved with a reduced retrogradation rate. Pea starch responded to the high-pressure homogenization process well. Compared with the rice and maize starch reported in the literature, pea starch required a reduced amount of gallic acid to form a high level of complexation with a significant delay in starch digestion.

The Influence of Starch Origin on the Properties of Starch Films: Packaging Performance

Starch films can be used as materials for food packaging purposes. The goal of this study is to compare how the starch origin influence the selected starch film properties. The films were made from various starches such as that from maize, potato, oat, rice, and tapioca using 50%_w of glycerine as a plasticizer. The obtained starch-based films were made using the well-known casting method from a starch solution in water. The properties of the films that were evaluated were tensile strength, water vapour transition rate, moisture content, wettability, and their surface free energy. Surface free energy (SFE) and its polar and dispersive components were calculated using the Owens-Wendt-Rabel-Kaelbe approach. The values of SFE in the range of 51.64 to 70.81 mJ∙m⁻² for the oat starch-based film and the maize starch-based film. The films revealed worse mechanical properties than those of conventional plastics for packaging purposes. The results indicated that the poorest tensile strength was exhibited by the starch-based films made from oat (0.36 MPa) and tapioca (0.78 MPa) and the greatest tensile strength (1.49 MPa) from potato.

Development, modification and characterization of new biodegradable film from basil seed (Ocimum basilicum L.) mucilage

BACKGROUND

Biodegradable films from basil seed mucilage (BSM) were formed and modified with several di-carboxylic acid crosslinkers; i.e. tartaric acid (TA), malic acid (MA) and succinic acid (SA) with varying acidity and chemical structures, to enhance mechanical properties and water barrier ability. Basil seeds have a reasonable mucilage content and valuable properties; thus, it has the potential to develop valuable new biodegradable films.

RESULT

We characterized BSM films with the three crosslinkers using Fourier-transform infrared (FTIR) spectra and observed a 1730 cm^-1 CO stretching peak, which confirmed ester linkage between the mucilage and crosslinkers. The crosslinked films showed higher gel fraction than native films. The crosslinked films showed better swelling and water vapor permeability with SA than with TA and MA. Crosslinking led to significant improvement in strain at maximum load. Further, the stress maximum load was comparable to that of commercial low-density polyethylene (LDPE) film. Crosslinked films showed additional homogeneous morphology and an increase in thermal degradation temperatures.

CONCLUSION

Crosslinking with dicarboxylic acids improved all the key properties of BSM films, including excellent stress and strain at maximum load, improved barrier capability and thermal properties. Thus, these films showed good potential as biodegradable films, especially for food packaging. © 2019 Society of Chemical Industry.