Effects of microwave, ultrasound, and high-pressure homogenization on the physicochemical properties of sugarcane fibre and its application in white bread

Sugarcane fibre (SCF) is known as an insoluble dietary fibre and a by-product from sugar manufacturing industry. The physicochemical and structural properties of SCF were modified using microwave irradiation at 5% and 10% SCF for 5 and 10 min (MW5%,15m, MW10%,5m, MW10%,15m), ultrasound at 30% amplitude, 7% SCF, for 1.5 h or 3 h (US1h, US2h), and high-pressure homogenization at 1% SCF, 2000 bar for 1 and 2 passes (HPH1p, HPH2p). Different types of disruption on the morphology of SCF were observed with different physical treatments confirmed by scanning electron microscopy. HPH2p treated SCF exhibited the largest particle size, and highest water and oil-holding capacities. Fourier-transform infrared spectroscopy results showed that all physical treatments were able to reduce hemicellulose and enhance cellulose content in SCFs, especially for HPH treatments. After making dough and bread with treated and untreated SCF, HPH2p SCF incorporated bread had the firmest texture, followed by MW10%,15m, while these two samples have the lowest specific volume. The maximum height of bread was significantly lower in breads incorporated with HPH2p, US1.5h and US3h. Subsequently, glycemic response decreased in all SCF-incorporated breads compared to white bread reference.