Extruded Unripe Plantain Flour as an Indigestible Carbohydrate-Rich Ingredient.

Daniel E Garcia-Valle,Juscelino Tovar,Edith Agama-Acevedo,Pamela C Flores-Silva,Luis A Bello-Perez

doi:10.3389/fnut.2019.00002

Daniel E Garcia-Valle, Juscelino Tovar + Show 3 more

Open Access

https://doi.org/10.3389/fnut.2019.00002

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Abstract

There is a growing interest in the development of functional ingredients, including those with high indigestible carbohydrate content. Unripe plantain flour (UPF) is a source of indigestible carbohydrates, type II resistant starch (RS) in particular. A major drawback of UPF, however, is that its RS content decreases sharply after wet heat treatment. Here, we explore the possibility of preparing an extruded UPF-based functional ingredient that retains limited starch digestibility features and high dietary fiber content. Both an unripe plantain pulp flour (UPFP) and a whole (pulp and peel) unripe plantain flour (UPFW) were prepared, extruded under identical conditions and evaluated for their gelatinization degree, total starch (TS), resistant starch (RS), and total dietary fiber (TDF) content; functional properties, such as pasting profile, water retention capacity, and solubility, and oil absorption index were also analyzed. The extruded functional ingredient was added to a yogurt and the rheological characteristics and in vitro starch digestibility of the product were evaluated. The extruded UPFW showed a lower gelatinization degree than the extruded UPFP, which may be due to the higher non-starch polysaccharide content of the former. A high TDF content was recorded in both extrudates (12.4% in UPFP and 18.5% in UPFW), including a significant RS fraction. The water retention capacity and solubility indices were higher in the extruded flours, particularly in UPFW, while only marginal differences in oil retention capacity were observed among the products. The addition of UPFP or UPFW (1.5 g TDF, w/v) to a yogurt did not alter the viscosity of the product, an important characteristic for the consumer's approval. Moreover, the composite yogurt showed a relatively low starch digestion rate. Extrusion of UPFs may be an alternative for the production of functional ingredients with important DF contents.

Highlights

IntroductionThe end-use of plantain and other varieties of banana has increased around the world
In the last years, the end-use of plantain and other varieties of banana has increased around the world
No differences were found in the dietary fiber content (≈ 30) of spaghettis elaborated with pulp-derived unripe plantain flour (UPF) compared to those made of whole fruit UPF [9]

Summary

Introduction

The end-use of plantain and other varieties of banana has increased around the world. There are diverse studies of the use of unripe plantain flour (UPF) in its native state; when this flour is incorporated in heat-treated foods, such as bakery products, snacks, and pasta [2,3,4], the cooking process largely decreases the indigestible carbohydrate content due to RS conversion to digestible starch. The above-mentioned studies have focused on the modification of UPF prepared from the pulp of the fruit; in order to decrease the production costs and to increase both the yield and dietary fiber content of UPF, the use the whole fruit (pulp and peel) has been suggested Such an alternative was tested to produce gluten-free spaghetti. No differences were found in the dietary fiber content (≈ 30) of spaghettis elaborated with pulp-derived UPF compared to those made of whole fruit UPF [9]

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