Sweetpotato-based complementary food would be less inhibitory on mineral absorption than a maize-based infant food assessed by compositional analysis

Bioavailability of Selected Micronutrients in Teff-based Complementary Infant Foods

Background:

The problem of micronutrient malnutrition is affecting millions of infants in the developing countries. One of the major issues that aggravates the problem is lack of appropriately processed complementary foods in which the bioavailability of the major micronutrients is improved.

Methods:

Teff, soybean and orange-fleshed sweet potato were separately processed into their respective flours and blended in a ratio of 70:20:10, respectively, to prepare household- and industrial-level complementary foods. The ingredients and developed complementary foods were analysed for their vitamin A, calcium, iron, zinc and phytate contents. Moreover, phytate: mineral molar ratios of calcium, iron and zinc in the complementary foods were calculated to determine their bioavailability.

Results:

The vitamin A values obtained in the complementary foods were appreciable; they were in the range of 91.89 to 160.97 µgRE/100 g. Phytate content of teff and soybean was significantly (p ≤ 0.05) reduced by the household practices employed for processing them. However, the reduction was not significant (p > 0.05) in the household-level complementary foods because of the small quantity of germinated teff flours used. Calcium, iron and zinc compositions of all complementary foods closely met the recommended levels for 6 to 8 month-old infants. Phytate: mineral molar ratios for calcium and zinc in all complementary foods were below maximum recommended limits indicating their good bioavailability. In case of iron, these ratios were above the critical limit except that of the industriallevel complementary foods.

Conclusion:

Generally, complementary foods with improved compositions and bioavailability of the micronutrients analysed were developed from the teff-soybean-orange-fleshed sweet potato formulations.

Nutrient and Total Polyphenol Contents of Dark Green Leafy Vegetables, and Estimation of Their Iron Bioaccessibility Using the In Vitro Digestion/Caco-2 Cell Model

Dark green leafy vegetables (DGLVs) are considered as important sources of iron and vitamin A. However, iron concentration may not indicate bioaccessibility. The objectives of this study were to compare the nutrient content and iron bioaccessibility of five sweet potato cultivars, including three orange-fleshed types, with other commonly consumed DGLVs in Ghana: cocoyam, corchorus, baobab, kenaf and moringa, using the in vitro digestion/Caco-2 cell model. Moringa had the highest numbers of iron absorption enhancers on an “as-would-be-eaten” basis, β-carotene (14169 μg/100 g; p < 0.05) and ascorbic acid (46.30 mg/100 g; p < 0.001), and the best iron bioaccessibility (10.28 ng ferritin/mg protein). Baobab and an orange-fleshed sweet potato with purplish young leaves had a lower iron bioaccessibility (6.51 and 6.76 ng ferritin/mg protein, respectively) compared with that of moringa, although these three greens contained similar (p > 0.05) iron (averaging 4.18 mg/100 g) and β-carotene levels. The ascorbic acid concentration of 25.50 mg/100 g in the cooked baobab did not enhance the iron bioaccessibility. Baobab and the orange-fleshed sweet potato with purplish young leaves contained the highest levels of total polyphenols (1646.75 and 506.95 mg Gallic Acid Equivalents/100 g, respectively; p < 0.001). This suggests that iron bioaccessibility in greens cannot be inferred based on the mineral concentration. Based on the similarity of the iron bioaccessibility of the sweet potato leaves and cocoyam leaf (a widely-promoted “nutritious” DGLV in Ghana), the former greens have an added advantage of increasing the dietary intake of provitamin A.

Iron Bioavailability and Provitamin A from Sweet Potato- and Cereal-Based Complementary Foods

Iron and vitamin A deficiencies in childhood are public health problems in the developing world. Introduction of cereal-based complementary foods, that are often poor sources of both vitamin A and bioavailable iron, increases the risk of deficiency in young children. Alternative foods with higher levels of vitamin A and bioavailable iron could help alleviate these micronutrient deficiencies. The objective of this study was to compare iron bioavailability of β-carotene-rich sweet potato-based complementary foods (orange-flesh based sweet potato (OFSP) ComFa and cream-flesh sweet potato based (CFSP) ComFa with a household cereal-based complementary food (Weanimix) and a commercial cereal (Cerelac^®), using the in vitro digestion/Caco-2 cell model. Iron bioavailability relative to total iron, concentrations of iron-uptake inhibitors (fibre, phytates, and polyphenols), and enhancers (ascorbic acid, ß-carotene and fructose) was also evaluated. All foods contained similar amounts of iron, but bioavailability varied: Cerelac^® had the highest, followed by OFSP ComFa and Weanimix, which had equivalent bioavailable iron; CFSP ComFa had the lowest bioavailability. The high iron bioavailability from Cerelac^® was associated with the highest levels of ascorbic acid, and the lowest levels of inhibitors; polyphenols appeared to limit sweet potato-based food iron bioavailability. Taken together, the results do not support that CFSP- and OFSP ComFa are better sources of bioavailable iron compared with non-commercial/household cereal-based weaning foods; however, they may be a good source of provitamin A in the form of β-carotene.

Orange-fleshed sweet potato-based infant food is a better source of dietary vitamin A than a maize-legume blend as complementary food

BACKGROUND

White maize, which is widely used for complementary feeding and is seldom fortified at the household level, may be associated with the high prevalence of vitamin A deficiency among infants in low-income countries.

OBJECTIVE

The nutrient composition of complementary foods based on orange-fleshed sweet potato (OFSP) and cream-fleshed sweet potato (CFSP), maize-soybean-groundnut (Weanimix), and a proprietary wheat-based infant cereal (Nestlé Cerelac) were assessed using the Codex Standard (CODEX STAN 074-1981, Rev. 1-2006) specification as a reference. Additionally, the costs of OFSP complementary food, CFSP complementary food, and Weanimix production at the household level were estimated. Phytate and polyphenols, which limit the bioavailability of micronutrients, were assessed.

METHODS

Energy, macronutrients, and micronutrients listed as essential composition in the Codex Standard were determined and expressed as energy or nutrient density.

RESULTS

All the formulations met the stipulated energy and nutrient densities as specified in the Codex Standard. The beta-carotene content of OFSP complementary food exceeded the vitamin A specification (60 to 180 microg retinol activity equivalents/100 kcal). All the formulations except Weanimix contained measurable amounts of ascorbic acid (> or = 32.0 mg/100 g). The level of phytate in Weanimix was highest, about twice that of OFSP complementary food. The sweet potato-based foods contained about twice as much total polyphenols as the cereal-based products. The estimated production cost of OFSP complementary food was slightly higher (1.5 times) than that of Weanimix.

CONCLUSIONS

OFSP complementary food is a good source of beta-carotene and would therefore contribute to the vitamin A requirements of infants. Both OFSP complementary food and Weanimix may inhibit iron absorption because of their high levels of polyphenols and phytate, respectively, compared with those of Nestlé Cerelac.

The impact of in vitro digestion on bioaccessibility of polyphenols from potatoes and sweet potatoes and their influence on iron absorption by human intestinal cells

The composition of potatoes as determined by chemical extraction has been described extensively. It is thus quite well known that, among other compounds, potato is rich in polyphenols, vitamins and in some minerals. This paper underlines the important role of simulated gastro-intestinal in vitro digestion in the bioaccessibility of polyphenols (chlorogenic acid and derivatives, and rutin) from potatoes and sweet potatoes and their impact on iron uptake. Concentrations of polyphenols in the flesh of two potato cultivars (Nicola, white potato, and Vitelotte, purple potato) and sweet potato were measured by Ultra Performance Liquid Chromatography after boiling and after in vitro digestion. Chemical extraction underestimates polyphenol amounts that can be released during digestion and that are actually bioaccessible. Iron uptake, as evaluated by a ferritin assay, by intestinal human cells was decreased after incubation with the intestinal phase of in vitro digestion, presumably due to the presence of polyphenols.

Carbohydrate composition, viscosity, solubility, and sensory acceptance of sweetpotato- and maize-based complementary foods

Background

Cereal-based complementary foods from non-malted ingredients form a relatively high viscous porridge. Therefore, excessive dilution, usually with water, is required to reduce the viscosity to be appropriate for infant feeding. The dilution invariably leads to energy and nutrient thinning, that is, the reduction of energy and nutrient densities. Carbohydrate is the major constituent of food that significantly influences viscosity when heated in water.

Objectives

To compare the sweetpotato-based complementary foods (extrusion-cooked ComFa, roller-dried ComFa, and oven-toasted ComFa) and enriched Weanimix (maize-based formulation) regarding their 1) carbohydrate composition, 2) viscosity and water solubility index (WSI), and 3) sensory acceptance evaluated by sub-Sahara African women as model caregivers.

Methods

The level of simple sugars/carbohydrates was analysed by spectrophotometry, total dietary fibre by enzymatic-gravimetric method, and total carbohydrate and starch levels estimated by calculation. A Rapid Visco™ Analyser was used to measure viscosity. WSI was determined gravimetrically. A consumer sensory evaluation was used to evaluate the product acceptance of the roller-dried ComFa, oven-toasted ComFa, and enriched Weanimix.

Results

The sweetpotato-based complementary foods were, on average, significantly higher in maltose, sucrose, free glucose and fructose, and total dietary fibre, but they were markedly lower in starch content compared with the levels in the enriched Weanimix. Consequently, the sweetpotato-based complementary foods had relatively low apparent viscosity, and high WSI, than that of enriched Weanimix. The scores of sensory liking given by the caregivers were highest for the roller-dried ComFa, followed by the oven-toasted ComFa, and, finally, the enriched Weanimix.

Conclusion

The sweetpotato-based formulations have significant advantages as complementary food due to the high level of endogenous sugars and low starch content that reduce the viscosity, increase the solubility, impart desirable sensory characteristics, and potentially avoid excessive energy and nutrient thinning.