Effect of processing and oil type on carotene bioaccessibility in traditional foods prepared with flour and puree from orange‐fleshed sweetpotatoes

Effect of Orange-Fleshed Sweet Potato Purée and Wheat Flour Blends on β-Carotene, Selected Physicochemical and Microbiological Properties of Bread

Partial substitution of wheat flour with orange-fleshed sweet potato (OFSP) purée in bread can increase vitamin A intake among consumers. The study investigated the influence of wheat flour substitution with 20–50% of OFSP purée on proximate composition, color, β-carotene, water activity, and microbial keeping quality. The moisture content, crude protein, crude fat, total ash, crude fiber, and carbohydrate in bread ranged from 28.6–32.7%, 9.9–10.6%, 5.0–5.5%, 1.9–3.2%, 1.4–1.8%, and 79.1–80.9%, respectively. β-carotene, total ash, and crude fiber contents in bread, and Hunter color values a*, b*, chroma, and ∆E significantly increased with the addition of OFSP purée. Total viable counts (TVC), yeast, and molds in bread ranged from 2.82–3.64 log10 cfu/g and 1.48–2.16 log10 cfu/g, respectively, on the last day of storage. Water activity, TVC, and fungal counts were low in sweet potato composite bread as compared to white bread. Total β-carotene in OFSP bread ranged from 1.9–5.4 mg/100 g (on dry weight). One hundred grams of bread portion enriched with 40% and 50% OFSP purée provides more than 50% of vitamin A dietary requirements to children aged 4–8 years. Incorporation of up to 50% OFSP purée in wheat flour produces a relatively shelf-stable, nutritious, and health-promoting functional bread.

Starch digestibility and β-carotene bioaccessibility in the orange- fleshed sweet potato puree-wheat bread

Vitamin A is essential for vision, human health, growth, immune function, and reproduction. Its deficiency leads to anemia, xerophthalmia, and growth reduction in children. Foods enriched with naturally occurring carotenes have the potential, in this regard, and orange-fleshed sweet potato (OFSP) stands out tall as it is rich in β-carotene (βC), a provitamin A carotenoid. In view of developing OFSP-based functional foods to address the vitamin A deficiency (VAD) issues, herein, OFSP puree-wheat composite breads have been prepared at 10% to 50% OFSP puree concentrations and bioaccessibility of βC has been estimated. The total βC is found to be 4.3, 9.2, 16.5, 23.3, and 33.6 µg/g in 10, 20, 30, 40, and 50% OFSP bread, respectively. The corresponding calculated retinol activity equivalents (RAE) are 30.9, 66.4, 119.5, 170.4, and 246.2 RAE/100 g. The efficiency of micellarization of all-trans-βC, 13-cis βC, and 9-cis βC after simulated oral, gastric, and small intestinal digestion are 1.4% to 6.4%, 1.4% to 7.2%, and 1.1% to 6.9%, respectively. The amount of micellarized βC correlates linearly with the OFSP concentration in the bread. Furthermore, in vitro starch digestion decreases with significant reduction in the Rapidly Digestible Starch (RDS) amount coupled with increase in the Slowly Digestible Starch (SDS) and Resistant Starch (RS) fractions. Overall, OFSP-wheat composite bread holds adequate amount of provitamin A carotenoids. The amount of bioaccessible βC coupled with altered starch digestion of the OFSP wheat breads highlight their usefulness as novel functional foods that could address the VAD as well as glycemic issues toward improving human health.

Evaluation of processing methods and oral mastication on the carotenoid bioaccessibility of restructured carrot chips

BACKGROUND

Carrot carotenoids are typically located in chromoplasts, forming a crystalline substructure. Cell walls and chromoplasts therefore constitute two major physical barriers to the release of carotenoids from the food matrix during digestion. The release of carotenoids from these physical barriers is supposed to be substantially affected by mechanical factors during food processing and oral mastication. Given the implications of this, the effects of four different processing procedures, and various mastication levels, on the carotenoid bioaccessibility of carrot chips were evaluated.

RESULTS

Restructuring and drying methods substantially affected the carotenoid bioaccessibility of carrot chips. The highest carotenoid bioaccessibility was obtained for the air-dried combined with instant pressure-drop-dried (AD-DIC) restructured chips. Although the fresh carrots possessed the highest carotenoid content, their bioaccessibility was lower than that of the carrot chips. The evolution of the particle sizes of the samples was responsible for the changes in carotenoid bioaccessibility due to oral masitication. The particle size of the fresh carrots decreased with increasing oral masitication, which favored carotenoid bioaccessibilty. However, the restructured chips that combined freeze drying with instant pressure-drop drying (R-FD-DIC) demonstrated the opposite trend, probably caused by the severe aggregation of the sample during digestion, which compromised the effect of mastication on the release of carotenoid.

CONCLUSION

Data regarding the effects of the drying process and oral mastication digestion behavior on the samples suggested that AD-DIC-dried restructured carrot chips are effective in enhancing carotenoid bioaccessibility, which explains the key factors involved in the release of carotenoids from carrot chips prepared by different processes. © 2020 Society of Chemical Industry.

What is food-to-food fortification? A working definition and framework for evaluation of efficiency and implementation of best practices

Food-to-food fortification (FtFF) is an emerging food-based strategy that can complement current strategies in the ongoing fight against micronutrient deficiencies, but it has not been defined or characterized. This review has proposed a working definition of FtFF. Comparison with other main food-based strategies clearly differentiates FtFF as an emerging strategy with the potential to address multiple micronutrient deficiencies simultaneously, with little dietary change required by consumers. A review of literature revealed that despite the limited number of studies (in vitro and in vivo), the diversity of food-based fortificants investigated and some contradictory data, there are promising fortificants, which have the potential to improve the amount of bioavailable iron, zinc, and provitamin A from starchy staple foods. These fortificants are typically fruits and vegetables, with high mineral as well as ascorbic acid and β-carotene contents. However, as the observed improvements in micronutrient bioavailability and status are relatively small, measuring the positive outcomes is more likely to be impactful only if the FtFF products are consumed as regular staples. Considering best practices in implementation of FtFF, raw material authentication and ingredient documentation are critical, especially as the contents of target micronutrients and bioavailability modulators as well as the microbiological quality of the plant-based fortificants can vary substantially. Also, as there are only few developed supply chains for plant-based fortificants, procurement of consistent materials may be problematic. This, however, provides the opportunity for value chain development, which can contribute towards the economic growth of communities, or hybrid approaches that leverage traditional premixes to standardize product micronutrient content.