Bambusa vulgaris starch: Characterization and technological properties

The starch industry has grown quickly, and starch production has expanded around the world because it is a very versatile ingredient, despite limits in some foodstuffs. So, this study aimed to analyze morphology, physic and chemical characteristics of the starch extracted from three different parts (bottom, middle and top) of the young bamboo culm of B. vulgaris (SB, SM, and ST, respectively). The obtained data were evaluated by analysis of variance and Scott-Knot test (p < 0.05), and no significant difference was observed between SB, SM and ST samples. The starches presented yellowish coloration (L* > 88, a* > -0.2, and b* > 9), and SEM images showed compound granules with polyhedral shapes and average diameter of 6.55 µm; apparent amylose content of 37.45%, wherein SB and SM showed characteristics of resistant starch type 2, whereas ST was more similar to normal starch. Amylopectin presented high proportion of chains with DP 13-24 and lower proportion of long chains, corroborating with A-type crystalline pattern. The absence of a shoulder in the branch chain length distribution, suggest a perfect crystalline structure, similar to starches from D. asper and B. tuldoides. DSC shows gelatinization temperatures higher than 80 °C, lower transition temperatures and the percentage of retrogradation above 44%. The results are promising to obtain slow digesting starches, although it is necessary to evaluate the starch from other bamboo species, which may have different characteristics.