Physicochemical properties and in vitro digestibility of potato starch after inclusion with vanillic acid

Citation

Dupuis, J.H., Tsao, R., Yada, R.Y., Liu, Q. (2017). Physicochemical properties and in vitro digestibility of potato starch after inclusion with vanillic acid. Food Science and Technology - LWT, [online] 85 218-224. http://dx.doi.org/10.1016/j.lwt.2017.07.010

Plain language summary

Physicochemical Properties and In Vitro Digestibility of Potato Starch After Inclusion with Vanillic Acid

John H. Dupuis, Rong Tsao, Rickey Y. Yada, Qiang Liu

Novel potato foods and starch products with enhanced amounts of slowly digestible starch (SDS) and/or resistant starch (RS) are highly demanded for human health benefits. The purpose of this work was to create novel Vanillic Acid (VA)-amylose complexes, and subsequently determine the physicochemical properties of these modified starches. In this study, 5 or 10% VA was added to potato starch on a dry weight basis at various pH levels (3, 5, 7, 9, & 11). We characterized the antioxidant, gelatinization, and pasting properties, x-ray diffraction patterns with the crystalline/amorphous character of the modified starch. In addition, the in vitro digestibility of the starches in both native and cooked form was also undertaken. This study demonstrated that the addition of VA to native potato starch granules in slurries at various pH values had no positive effect on the resistant starch content of either native or cooked starch samples. Overall, low amounts of VA were incorporated, which was reflected by the antioxidant levels. Both total phenolic content and antioxidant activity generally increased over the control. In all cases the gelatinization temperature range was significantly decreased, which was likely an artifact of the mild hydro-thermal treatment. A much more profound impact was made on the pasting properties of the starch, notably peak, trough, breakdown, final viscosity, and pasting time. The resistant starch (RS) content of modified starches ranged from 52-77%; in cooked samples, RS was not significantly different from the control, and ranged from 12-15%. Thus, VA-starch complexes may result in a functional/healthier food with the ability to both lower carbohydrate digestibility while having antioxidant ability to have significant impacts on human health. Novel modified starch products will be developed as a functional food ingredient in the near future based on this research.

Abstract

While research regarding phytochemicals has been topical due to their many positive health effects, modification of starch with phytochemical fractions has been limited. In the current study, 50 or 100 mg/g of vanillic acid (VA), which possesses antioxidant activity and positive health effects, was added to potato starch on a dry weight basis at various pH levels (3, 5, 7, 9, & 11). Both total phenolic content and antioxidant activity generally increased over the control. X-ray diffraction detected no V-amylose peaks indicating a lack of amylose-VA inclusion complexes. In addition, a decrease in the ratio of 1045/1015 cm−1 was measured by FTIR denoting a loss of crystalline order. Enthalpy of gelatinization was unaffected in most samples, however, Tc–To was significantly (p < 0.05) reduced in all modified starches. Trough viscosity, final viscosity, and pasting time all significantly increased with increasing pH (p < 0.05), and peak viscosity reached a maximum of 11360 mPa·s. The resistant starch (RS) content of modified starches ranged from 51.71 to 77.16 g/100 g; in cooked samples, RS was not significantly different from the control, and ranged from 11.66 to 15.10 g/100 g.

Publication date

2017-11-01