Current trends in the preparation, characterization and applications of oat starch - A review

Structure and functional characteristics of starch from different hulled oats cultivated in China

This work aimed to evaluate the structure and functional characteristics of starch from ten hulled oat cultivars grown in different locations in China. The protein, phosphorus, amylose, and starch contents were 0.2-0.4 %, 475.7-691.8 ppm, 16.2-23.0 %, and 93.6-96.7 %, respectively. All the starches showed irregular polygonal shapes and A-type crystallization with molecular weights ranging from 7.2 × 107 to 4.5 × 108 g/mol. The amounts of amylopectin A (DP 6-12), B1 (DP 13-24), B2 (DP 25-36), and B3 (DP > 36) chains were in the ranges of 10.3-16.0 %, 54.5-64.8 %, 16.5-21.1 %, and 4.9-13.1 %, respectively. The starches differed significantly in gelatinization temperatures, pasting viscosity, solubility, swelling power, rheological properties, and digestion parameters. The results revealed that the larger particle size could increase the peak viscosity of the starch paste. The presence of phosphorus increased the gelatinization temperature and enhanced the resistant starch content. The starch granules with higher crystallinity contained a higher proportion of phosphate, which increased final viscosity and setback viscosity but decreased rapidly digestible starch. Overall, oat starch with a high phosphorus content could be used to prepare low-glycemic-index food for diabetes patients.

Starch from Unripe Apples (Malus domestica Borkh) as an Alternative for Application in the Food Industry

This study investigated the properties of starch isolated from the unripe fruit of two apple cultivars (Malus domestica Borkh) grown in southern Poland (Central Europe). The chemical composition of both starches, molecular mass, their granulation, thermal characteristics, swelling characteristics, and rheological characteristics were studied. The starches differed significantly in ash, phosphorus, and protein content. The water-binding capacity at temperatures of 25-65 °C was similar, while differences of 20% appeared at higher temperatures. In contrast, a significant difference was found in the solubility of the two starches in the temperature range of 25-75 °C. The study showed that apple starches have a relatively low tendency to retrograde, with the enthalpy of gelatinization for starch from the Oliwka variety being 40% higher than that from the Pyros variety. However, the starches differed in the hardness of the gels formed, i.e., one variety formed soft gels with an internal structure resistant to external forces, while the other formed hard gels.

The combined actions of the granule surface barrier and multiscale structural evolution of starch on in vitro digestion of oat flour

The digestive properties of oat-based food have garnered considerable interest. This study aimed to explore the internal and external factors contributing to different digestion properties of oat flour under actual processing conditions. Analysis of the ordered structure of oat starch revealed that an increase in gelatinization moisture to 60 % led to a decrease in crystallinity, R1047/1022 value, and helical structures content to 0, 0.48 %, and 1.45 %, respectively. Even when the crystal structure was completely destroyed, the short-range structure retained a certain degree of order. Surface structure observations of starch granules and penetration experiments with amylase-sized polysaccharide fluorescence probes indicated that non-starch components and small pores effectively hindered the diffusion of the probes but low-moisture (20 %) gelatinization substantially damaged this barrier. Furthermore, investigations into starch digestibility and starch molecular structure revealed that the ordered structure remaining inside the starch after high gelatinization delayed the digestion rate (0.028 min-1) and did not increase the content of resistant starch (7.10 %). It was concluded that the surface structure and non-starch components of starch granules limited the extent of starch digestion, whereas the spatial barrier of the residual ordered structure affected the starch digestion rate.

Effect of operating conditions on structure and digestibility of spray-dried corn starch

Spray drying has been widely applied in food industry due to its efficiency and low cost. Exploring feasibility to prepare resistant starch (RS) via spray drying could open up new route to produce starch-based products with low glycemic index efficiently. In this study, effects of spray drying operating conditions on the structure and digestibility of recrystallized spray-dried corn starch (RSDCS) were explored. Apparent amylose content (AAC) and swelling power (SP) of the RSDCSs increased after the spray drying and recrystallization. Particle size of the RSDCSs decreased significantly with increase of compressed air flow and decrease of starch suspension concentration. Furthermore, the short-range order, long-range order, and content of RS in the RSDCSs decreased with increase of compressed air flow and starch suspension concentration. The Pearson's correlation analysis showed that digestive properties of the RSDCSs were mainly related to the short-range ordered structure and crystalline structure. Moreover, Mantel analysis revealed that operating conditions changed the digestibility of the RSDCSs through impacting crystalline structure, AAC and SP. The highest content of RS in the RSDCSs (23.08%) was increased near 2.6 times comparing to that of native corn starch (9.02%).

Structural, Thermal, Rheological, and Morphological Characterization of the Starches of Sweet and Bitter Native Potatoes Grown in the Andean Region

This study aimed to extract and characterize the morphological, physicochemical, thermal, and rheological properties of the starches of native potatoes grown in the department of Puno. Among the varieties evaluated were sweet native potato varieties Imilla Negra (Solanum tuberosum spp. Andígena), Imilla Blanca (Solanum tuberosum spp. Andígena), Peruanita, Albina or Lomo (Solanum chaucha), and Sutamari, and the bitter potatoes Rucki or Luki (Solanum juzepczukii Buk), Locka (Solanum curtilobum), Piñaza (Solanum curtilobum), and Ocucuri (Sola-num curtilobum), acquired from the National Institute of Agrarian Innovation (INIA-Puno). The proximal composition, amylose content, and morphological, thermal, and rheological properties that SEM, DSC, and a rheometer determined, respectively, were evaluated, and the data obtained were statistically analyzed using a completely randomized design and then a comparison of means using Tukey's LSD test. The results show a significant difference in the proximal composition (p ≤ 0.05) concerning moisture content, proteins, fat, ash, and carbohydrates. Thus, the amylose content was also determined, ranging from 23.60 ± 0.10 to 30.33 ± 0.15%. The size morphology of the granules is 13.09-47.73 µm; for the thermal and rheological properties of the different varieties of potato starch, it is shown that the gelatinization temperature is in a range of 57 to 62 °C and, for enthalpy, between 3 and 5 J/g.

Green composites based on thermoplastic starch reinforced with micro- and nano-cellulose by melt blending - A review

Starch is a biodegradable biopolymer, a sustainable material that can replace conventional petrochemical-based plastics. However, starch has some limitations, as it must be processed by heating and treated mechanically with a plasticizer to become thermoplastic starch (TPS). Different variables such as mixing speeds, amount, and kind of plasticizers play a vital role in preparing TPS by melting. Despite this, the properties of the TPS are not comparable with those of traditional plastics. To overcome this limitation, microcellulose or nanocellulose is added to TPS by melt mixing, including the extrusion and internal mixing process, which enables large-scale production. This review aims to compile several studies that evaluate the effect of plasticizers, as well as the relevance of incorporating different cellulosic fillers of different dimensions on the properties of TPS obtained by melt mixing. Potential applications of these materials in food packaging, biomedical applications, and other opportunities are also described.

A comprehensive review on oat milk: from oat nutrients and phytochemicals to its processing technologies, product features, and potential applications

Plant-based milk alternatives have become increasingly desirable due to their sustainability and the increased consumer awareness of health. Among many varieties of emerging plant-based milk, the smooth texture and flavor of oat milk make it spread rapidly around the world. Furthermore, as a sustainable source of diet, oats can provide rich nutrients and phytochemicals. Issues on the stability, sensory properties, shelf life, and nutritional quality of oat milk have been highlighted in published studies. In this review, the processing techniques, quality improvement, and product features of oat milk are elaborated, and the potential applications of oat milk are summarized. Besides, the challenges and future perspectives of oat milk production in the future are discussed.

The mitochondrial genome of the diploid oat Avena longiglumis

BACKGROUND

Avena longiglumis Durieu (2n = 2x = 14) is a wild relative of cultivated oat (Avena sativa, 2n = 6x = 42) with good agronomic and nutritional traits. The plant mitochondrial genome has a complex organization and carries genetic traits of value in exploiting genetic resources, not least male sterility alleles used to generate F₁ hybrid seeds. Therefore, we aim to complement the chromosomal-level nuclear and chloroplast genome assemblies of A. longiglumis with the complete assembly of the mitochondrial genome (mitogenome) based on Illumina and ONT long reads, comparing its structure with Poaceae species.

RESULTS

The complete mitochondrial genome of A. longiglumis can be represented by one master circular genome being 548,445 bp long with a GC content of 44.05%. It can be represented by linear or circular DNA molecules (isoforms or contigs), with multiple alternative configurations mediated by long (4,100-31,235 bp) and medium (144-792 bp) size repeats. Thirty-five unique protein-coding genes, three unique rRNA genes, and 11 unique tRNA genes are identified. The mitogenome is rich in duplications (up to 233 kb long) and multiple tandem or simple sequence repeats, together accounting for more than 42.5% of the total length. We identify homologous sequences between the mitochondrial, plastid and nuclear genomes, including the exchange of eight plastid-derived tRNA genes, and nuclear-derived retroelement fragments. At least 85% of the mitogenome is duplicated in the A. longiglumis nuclear genome. We identify 269 RNA editing sites in mitochondrial protein-coding genes including stop codons truncating ccmFC transcripts.

CONCLUSIONS

Comparative analysis with Poaceae species reveals the dynamic and ongoing evolutionary changes in mitochondrial genome structure and gene content. The complete mitochondrial genome of A. longiglumis completes the last link of the oat reference genome and lays the foundation for oat breeding and exploiting the biodiversity in the genus.

Investigation of the mechanism of different 3D printing performance of starch and whole flour gels from tuber crops

This study aims to reveal the variation in 3D printing performance of whole flour and starch gels as derived from different varieties of tuber crops including cassava, potato, and yam, along with its mechanism. The whole flour of the same tuber crops showed a higher branching degree, average molecular weight (R¯_h), and the proportion of AM chains for 100 < X ≤ 1000 than its starch. Due to the higher degree of branching, the crystallinity of whole flour reached a higher level. In this circumstance, G2' of the dispersion system decreased, which facilitated smooth extrusion of ink from the nozzle, thus improving the precision of printing for the final product. Besides, a higher R¯_h and the percentage of AM chains for 100 < X ≤ 1000 made it easier for the material to extrude, thus enhancing the printing accuracy of the product. The higher short-range ordered structure of whole flour also enhanced the printing performance of 3D printed products. This research contributes an effective solution to the selection of starch and whole flour for food 3D printing.

Carbohydrate polymer-based nanocomposites for breast cancer treatment

Breast cancer is known as the most common invasive malignancy in women with the highest mortality rate worldwide. This concerning disease may be presented in situ (relatively easier treatment) or be invasive, especially invasive ductal carcinoma which is highly worrisome nowadays. Among several strategies used in breast cancer treatment, nanotechnology-based targeted therapy is currently being investigated, as it depicts advanced technological features able of preventing drugs' side effects on normal cells while effectively acting on tumor cells. In this context, carbohydrate polymer-based nanocomposites have gained particular interest among the biomedical community for breast cancer therapy applications due to their advantage features, including abundance in nature, biocompatibility, straightforward fabrication methods, and good physicochemical properties. In this review, the physicochemical properties and biological activities of carbohydrate polymers and their derivate nanocomposites were discussed. Then, various methods for the fabrication of carbohydrate polymer-based nanocomposites as well as their application in breast cancer therapy and future perspectives were discussed.