Modification of insoluble dietary fiber from garlic straw with ultrasonic treatment

Abstract

The aim of this study was to investigate modification of insoluble dietary fiber (IDF) from garlic straw with ultrasonic processing technology. The functional, physicochemical, and structural properties were evaluated. Based on the uniform design (UD) method, initial temperature of 45 °C, ultrasonic power of 535 W, and time of 41 min were considered as the optimum ultrasonic conditions for preparation of IDF with good in vitro hypolipidemic ability. Ultrasonic‐treated IDF exhibited better functional and physicochemical properties than untreated IDF with significant difference (p < .05). Structural analysis from scanning electron microscope and Fourier transformed infrared spectroscopy indicated that ultrasonic treatment destroyed the microstructures of IDF from garlic straw, resulted in the honey‐comb network structure and increased hydrophilic groups, which illustrated the good functional and physicochemical properties. Practical applications With the trend toward increased consumption of garlic bulb, millions of tons of straw are generally discarded every year. The productive use of such by‐products as garlic straw could offer substantial economic benefits. In this work, ultrasonic technology was chosen for the modification of insoluble dietary fiber (IDF) from garlic straw. Uniform design technique helped us to get the optimum ultrasonic conditions for preparation of IDF with good in vitro hypolipidemic ability. The functional and physicochemical properties of garlic IDF were significantly influenced by ultrasonic pretreatment. The positive effect of ultrasound and application of the statistical model may be useful for functional modification and utilization of dietary fiber from garlic straw.

Preparation of cellulose with controlled molecular weight via ultrasonic treatment improves cholesterol‐binding capacity

“…Particularly, with a 30‐hr ultrasonic treatment, the CBC of cellulose were increased about 2.42 fold at pH 7.0 and 1.96 fold at pH 2.0, respectively. This demonstrates that the augmented cellulose samples have an improved CBC characteristic, in agreement to other IDF previously reported (Huang et al, ; Luo et al, ; Zhu et al, ).…”

“…In contrast, the untreated samples exhibited the lowest OHC (1.72 ± 0.15 g/g) among the samples. The cellulose via ultrasonic treatment might increase the specific surface area and capillary attraction, and consequently enhance the physical entrapment of oil (Chau, Wang, & Wen, ; Chen, Gao, Yang, & Gao, ), which is similar to the behavior of the modified IDF from garlic straw with ultrasonic treatment (Huang et al, ). The high OHC of the ultrasonic‐treated cellulose suggested their potential effects on cholesterol absorption as well.…”

“…The results showed that the ultrasonic‐treated cellulose possessed higher ( p < .05) binding capacity than the untreated cellulose sample at pH 2.0 and pH 7.0, respectively. This trend may be due to the loosening structure and larger surface area of the ultrasonic‐treated cellulose (Huang et al, ). Particularly, with a 30‐hr ultrasonic treatment, the CBC of cellulose were increased about 2.42 fold at pH 7.0 and 1.96 fold at pH 2.0, respectively.…”

“…For most cellulose, due to its stiff molecules and close chain packing via the inter‐ and intramolecular hydrogen bonds and glycosidic bonds, its characteristics of high Mw and insolubility in almost any solvents have been considered a limitation that blocks direct usage in the pharmaceutical and food fields (Pääkkö et al, ; PandeyMohamad & Amin, ). Nowadays, insoluble fiber is believed to contribute to cholesterol lowering and many other health benefits (Huang, Ding, Zhao, Li, & Ma, ), and it has been hypothesized that the cholesterol lowering capacities is highly correlated with the Mw of insoluble fiber. In addition, both dietary polymers dramatically compressed murine colonic mucus ex vivo and in vivo, and Mw of polymers played a role in this behavior (Datta, Preska, & Ismagilov, ).…”

“…usage in the pharmaceutical and food fields (Pääkkö et al, 2007;PandeyMohamad & Amin, 2014). Nowadays, insoluble fiber is believed to contribute to cholesterol lowering and many other health benefits (Huang, Ding, Zhao, Li, & Ma, 2017), and it has been hypothesized that the cholesterol lowering capacities is highly correlated with the Mw of insoluble fiber. In addition, both dietary polymers dramatically compressed murine colonic mucus ex vivo and in vivo, and Mw of polymers played a role in this behavior (Datta, Preska, & Ismagilov, 2016).…”