Study of unripe and inferior banana flours pre-gelatinized by four different physical methods

Siwei Zhang; Kangyun Zhao; Fei Xu; Xiaoai Chen; Kexue Zhu; Yanjun Zhang; Guanghua Xia

doi:10.3389/fnut.2023.1201106

Study of unripe and inferior banana flours pre-gelatinized by four different physical methods

Front Nutr. 2023 Jun 19:10:1201106. doi: 10.3389/fnut.2023.1201106. eCollection 2023.

Authors

Siwei Zhang^{1

2}, Kangyun Zhao², Fei Xu^{2

3}, Xiaoai Chen^{2

3}, Kexue Zhu^{2

3}, Yanjun Zhang^{2

3}, Guanghua Xia¹

Affiliations

¹ College of Food Science and Engineering, Hainan University, Haikou, Hainan, China.
² Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wanning, Hainan, China.
³ Key Laboratory of Processing Suitability and Quality Control of the Special Tropical Crops of Hainan Province, Wanning, Hainan, China.

Abstract

This study aimed to prepare the pre-gelatinized banana flours and compare the effects of four physical treatment methods (autoclaving, microwave, ultrasound, and heat-moisture) on the digestive and structural characteristics of unripe and inferior banana flours. After the four physical treatments, the resistant starch (RS) content values of unripe and inferior banana flours were decreased from 96.85% (RS2) to 28.99-48.37% (RS2 + RS3), while C∞ and k values were increased from 5.90% and 0.039 min^-1 to 56.22-74.58% and 0.040-0.059 min^-1, respectively. The gelatinization enthalpy (ΔHg) and I_1047/1022 ratio (short-range ordered crystalline structures) were decreased from 15.19 J/g and 1.0139 to 12.01-13.72 J/g, 0.9275-0.9811, respectively. The relative crystallinity decreased from 36.25% to 21.69-26.30%, and the XRD patterns of ultrasound (UT) and heat-moisture (HMT) treatment flours maintained the C-type, but those samples pre-gelatinized by autoclave (AT) and microwave (MT) treatment were changed to C + V-type, and heat-moisture (HMT) treatment was changed to A-type. The surface of pre-gelatinized samples was rough, and MT and HMT showed large amorphous holes. The above changes in structure further confirmed the results of digestibility. According to the experimental results, UT was more suitable for processing unripe and inferior banana flours as UT had a higher RS content and thermal gelatinization temperatures, a lower degree and rate of hydrolysis, and a more crystalline structure. The study can provide a theoretical basis for developing and utilizing unripe and inferior banana flours.

Keywords: digestive properties; four different treatments; starch; structure; unripe and inferior banana flours.