Starch is composed of amylose and amylopectin and deposited as granules of different sizes and shapes with semi-crystalline and amorphous concentric layers that show the 'maltese cross'. Starches from different sources show variable chemical composition as well as the structure of their components that are involved in thermal properties. Amylose, lipids, phosphorylated residues and long lateral chain amylopectin interact among them avoiding water uptake. In contrast, high amylopectin contents, especially with short lateral chains, allow hydration via hydrogen bonds to form gels with the tendency to retrogradation. Smaller starch granules have a larger superficial area, surface pores, and channels that enhance water uptake. High hydration increases the swelling, viscosity, and gelatinization ability of starch granules. The knowledge of those properties allows the selection of the most appropriate starch for a specific end use. This review discusses the relationship between the physicochemical composition of the starch and their rheological properties. Características Estructurales de Almidones y sus Propiedades Funcionales RESUMEN El almidón está compuesto de amilosa y amilopectina y es depositado en forma de gránulos de diferentes tamaños y formas con capas concéntricas que pueden ser semi-cristalinas o amorfas donde se observa la llamada cruz de Malta. Los almidones de diferentes fuentes varían en composición química, así como también en la estructura de sus componentes que están involucrados en las propiedades térmicas. La interacción entre amilosa, lípidos, residuos fosforilados y cadenas largas de amilopectina disminuye la absorción de agua. Lo opuesto sucede cuando se tiene un alto contenido de amilopectina con cadenas laterales cortas, gránulos de almidón pequeños, así como la existencia de poros superficiales y canales. Una alta hidratación de los gránulos de almidón aumenta el hinchamiento, viscosidad, habilidad de gelatinización y la retrogradación del gel después de largos tiempos de almacenamiento. El conocimiento de estas propiedades permite la selección de la fuente de almidón apropiada para un uso final específico.

Starches of developing triticale grains, differing in genome composition (complete AABBRR or substituted AABBDR), were evaluated in terms of starch granule distribution, dynamic rheological behaviour and microstructural characteristics on several days after anthesis. The starch granules were of an oblate spheroid shape for A-granules, and of a spherical shape for B-granules. However, those obtained from the complete triticale showed a larger diameter size. An X-ray diffraction analysis revealed the common A-type pattern of cereal starches from early development stages. A dynamic rheological analysis showed that the storage and loss moduli reached maximum levels in the temperature range of 71-86ºC and dropped at around 90ºC. Starches from the complete triticale showed lower phase transition temperatures, compared to those obtained from the substituted genotype (56.1±0.3 and 60.3±0.8°C, respectively). Scanning electron microscopy showed that the gels made with the starch of complete triticales were of a less dense sponge-like structure. K e y w o r d s: triticale developing grains, starch, gels, rheology, microstructure

The starch granules of complete and substituted triticale genotypes were analyzed for morphology and size distribution using scanning electron microscopy (SEM) and laser diffraction, respectively. A quantitative comparison of total carbohydrate, starch, and amylose contents was also performed. The results showed that the complete triticales contained 8.8% more total carbohydrate content and 13.8% more starch content than the substituted ones. No significant differences in the average amylose content (22.8%) were observed between the two sets of triticales. However, the A-and B-type starch granules of the substituted triticales showed significant differences in amylose content. Starch granule distribution profiles showed that the sizes of the A-and B-type starch granules of complete triticales were larger (in the range of 18-41 μm and 2-13 μm, respectively) than those of substituted triticales (in the range of 8-38 μm and 0.5-6 μm, respectively). This study demonstrated that the starch in triticale genotypes differs in physicochemical properties.Keywords: triticale; SEM; laser diffraction; starch; amylose; carbohydrate Se analizaron los gránulos de almidón de genotipos de triticales completos y sustituidos en morfología y distribución de tamaño utilizando microscopía electrónica de barrido (SEM, por sus siglas en inglés) y difracción láser, respectivamente. Se realizó una comparación cuantitativa del contenido de carbohidratos totales, almidón y amilosa. Los resultados mostraron que los triticales completos contienen 8,8% más en contenido de carbohidratos totales y 13,8% más de contenido de almidón que los triticales sustituidos. No se observaron diferencias significativas en el contenido de amilosa (promedio 22,8%), sin embargo, los gránulos de almidón tipo-A y tipo-B de los triticales sustituidos mostraron diferencias significativas en el contenido de amilosa, pero no los respectivos gránulos de los triticales completos. El análisis del perfil de distribución de los gránulos de almidón mostró que los gránulos de almidón tipo-A y tipo-B de los triticales completos son de mayor tamaño (rango de 18-41 μm y 2-13 μm, respectivamente) que el de los triticales sustituidos (rango de 8-38 μm y 0,5-6 μm, respectivamente). Se concluye que el almidón de los genotipos de triticales difieren en las propiedades fisicoquímicas estudiadas.

Fresh-cut fruits have been in great demand by consumers owing to the convenience of buying them in shopping centers as ready-to-eat products, and various advantages, such as the fact that they are healthy and fresh products. However, their shelf lives are brief due to their physiological changes and maturation. Therefore, this review includes information from the physicochemical, microbiological, nutritional, and sensory points of view on the deterioration mechanisms of fresh-cut fruits. In addition, updated information is presented on the different emerging technologies, such as active packaging (edible films, coatings, and modified atmospheres), natural preservatives (antioxidants and antimicrobials), and physical treatments (high hydrostatic pressure, UV-C radiation, and ozone). The benefits and disadvantages of each of these technologies and the ease of their applications are discussed. Having alternatives to preserve fresh-cut fruit is essential both for the consumer and the merchant, since the consumer could then obtain a high-quality product maintaining all its properties without causing any damage, and the merchant would receive economic benefits by having more time to sell the product.

Cereal Chem. 93(1):64-70The present work was carried out to make a comparison between the starch debranching enzyme activity and the synthesis of total carbohydrates, starch, amylose, and amylopectin in developing kernels of two sets of triticales differing in genome composition (complete and substituted triticales). The results showed that the carbohydrate and starch accumulation observed in both genotypes of triticales increased rapidly at the early stage, reaching the maximum at the medium stage and decreasing slightly or remaining relatively constant at the last stage of kernel development. At the end of the development stage, the mature grains of complete and substituted triticales accumulated 62.5 and 54.6% starch, respectively. Both sets of triticales showed the same amylose accumulation profile as well as degree of polymerization; however, at the maturity stage there was a small but significant difference between the two sets. The final polymerization values of amylose chains in mature seeds of complete and substituted triticales were DP 1,549 and 1,313. A and B 1 amylopectin chains of the complete triticales were approximately 19 and 33% shorter than those of the substituted triticales. The complete triticales showed higher isoamylase and pullulanase activities than the substituted triticales, which coincided with the highest starch and amylose contents observed in kernels under development. The results of this study demonstrate that the synthesis of starch differs between the triticale genotypes used in the study, which influences their chemical structure and physicochemical properties. † Corresponding