Powder structure and gelation behaviour of debranched cassava starches prepared with and without incubation

Abstract

The effect of incubation after debranching on the powder structure and gelation behaviour of debranched cassava starch (DBCS) was investigated. The DBCS samples were prepared by debranching 10% (w/v) cassava starch with pullulanase at 55 °C for 24 h, then incubated at 4 °C for 0, 1, 4, 24 and 72 h and recovered by precipitation with ethanol. The unincubated DBCS appeared as small, sponge-like aggregates with a rough surface, while the incubated DBCS powders were considerably larger, looked denser and had a smooth surface. The unincubated DBCS had an A + V-type crystal structure, whereas incubated DBCS samples had a B-type structure. Crystallinity of all DBCSs was 20-22%. The incubated DBCSs displayed a substantially lower gel setting time compared to the unincubated DBCS, that is, the gel setting time of 10% DBCSs cooked for 10 min reduced from 242 min to 47-52 min when kept at 25 °C. The difference of gel setting time was most likely related to the type of crystal formed as well as the difference in amorphous structure, as indicated by the content of the slowly digestible starch fraction.

Investigating the individual effects of salt, sucrose and native starch on the gelation and rheological behaviour of debranched cassava starch

“…The obtained DBCS exhibited a degree of hydrolysis of 4.35%, comprising 65.9% A chains, 22.1% B1 chains and 9.5% B2 + B3 chains from amylopectin, along with 2.5% longer chains from amylose with an average chain length of 23.5. The powders demonstrated a B-type crystal structure with 23% crystallinity and contained 31.2% resistant starch (RS) and 7.2% slowly digestible starch, as reported by Sari et al (2022). Sucrose was purchased from Ajax Finechem (NSW, Australia), and salt (sodium chloride) was purchased from QRec (New Zealand).…”

“…International Co., Ltd, Bangkok, Thailand) was purchased at a local market in Bangkok, Thailand. The DBCS utilised in this study was sourced from the same batch as reported by Sari et al (2022). Following the debranching of cassava starch using pullulanase, the resulting debranched product underwent a 24-h incubation at 4 °C before precipitation with ethanol and subsequent drying.…”

“…DBS with a sufficiently high degree of debranching and concentration can form stable gels that are distinct in appearance and texture from the gels of their native starch counterparts. Klaochanpong et al (2015) and Sari et al (2022) have found that gels from various DBSs are opaque, non-sticky, smooth and spreadable with a glossy appearance. Accordingly, DBS finds application as a versatile ingredient in food, cosmetics and pharmaceuticals, serving as a gelling agent, fat substitute, thickener, bulking agent, clouding agent or binder.…”

“…Previous studies by Klaochanpong et al (2015), Liu et al (2017), Precha-Atsawanan et al (2018a), Precha-Atsawanan et al (2018b), Liu et al (2018) and Wang et al (2022) have extensively investigated and documented DBS gels, showcasing characteristics such as stiffness and brittleness, with the presence of clusters of stiff polymers. Recently, Sari et al (2022) reported on the effect of incubation after debranching on the powder structure and gelation behaviour of debranched cassava starch. It is noteworthy that all these studies were conducted on gels formed by dispersing the DBS in water.…”

“…(2015) and Sari et al . (2022) have found that gels from various DBSs are opaque, non‐sticky, smooth and spreadable with a glossy appearance. Accordingly, DBS finds application as a versatile ingredient in food, cosmetics and pharmaceuticals, serving as a gelling agent, fat substitute, thickener, bulking agent, clouding agent or binder.…”