FNSFood and Nutrition Sciences2157-944XScientific Research Publishing10.4236/fns.2017.82016FNS-74309ArticlesBiomedical&Life Sciences Acceptability, Nutritional Quality and Contribution of Vegetable-Enriched Products to Nutrient and Energy Requirements of School Children Aged 5 to 13 Years NwataraliPhilomena Onwuamaeze1AchamHedwig1NakimbugweDorothy1Department of Food Technology and Nutrition, School of Food Technology, Nutrition and Bio-Systems Engineering, Makerere University, Kampala, Uganda070220170802242266May 25, 2016Accepted: February 21, February 24, 2017© Copyright 2014 by authors and Scientific Research Publishing Inc. 2014This work is licensed under the Creative Commons Attribution-NonCommercial International License (CC BY-NC).http://creativecommons.org/licenses/by-nc/4.0/

Micronutrient deficiency (MD) is a problem among schoolchildren which, in addition to other effects, also affects their intellectual abilities. Inclusion of vegetables to food formulations can help to reduce MD because they contain vital micronutrients which are required for improved school performance. This study aimed at evaluating acceptability, determining the nutritional quality and estimating the contribution of vegetable enriched products to the Recommended Dietary Allowance (RDA) of schoolchildren (5 to 13 years). The vegetables used were red and green amaranth leaves, orange fleshed sweet potato and pumpkin. Selection of vegetables was based on richness in micronutrients; local availability and consumption levels in Uganda; and their underutilization status particularly in processed form. Each of the vegetables was preprocessed and incorporated separately into soybean and grain amaranth in the ratio of 10:40:50, respectively, to improve the nutrient and energy density of the formulations. Sensory screening of formulations in a range of products (porridges, soups and snacks) revealed that orange fleshed sweet potato formulation was most preferred for porridge as well as for snacks (at 30:70 ratio of orange fleshed sweet potato composite to wheat flour); while red amaranth leaves composite was most preferred for soup. When tested for acceptability, nutritional quality, as well as contribution to the RDA (for vitamin A, iron, zinc, protein and energy) for schoolchildren 5 to 13 years, acceptability tests and nutritional quality of food products from the formulations were highly rated compared to commercial products (pure maize porridge, wheat based soup and 100% refined wheat flour snacks). All products from the two formulations contributed favourably to vitamin A, iron, zinc and protein requirements of children (5 to 13 years). Based on these findings, orange fleshed sweet potato composite flour can be recommended for making porridge, and can substitute (30%) for wheat flour in making snacks; while red amaranth leaf composite flour can be recommended for making soups.

Micronutrient School Age Children Vegetables Acceptability Nutritional Quality1. Introduction

Today micronutrient nutrition is gaining much recognition worldwide due to large spread of micronutrient deficiencies (MD’s) especially in developing countries. Roughly, two billion people (about one third of the world’s population) are deficient in one or more micronutrients [1] . MD can have major adverse health effects contributing to growth impairments, immune incompetence, mental and physical development retardation, and poor reproductive outcomes [2] [3] that cannot always be reversed by nutrition interventions [1] . The global concern of MD among children is iron, vitamin A and zinc [4] of which the deficiency is a problem among school going children.

Vegetables are essential for combating MD in the developing world; they are rich in vital micronutrients such as carotenes, vitamins and minerals, as well as dietary fibre [5] . Vegetables such as pumpkin, orange-fleshed sweet potatoes (OFSP) and leafy vegetables like red and green amaranth leaves (A. cruentus and A. lividus; respectively), are food sources of pro vitamin A carotenoids [6] and lots of minerals which can contribute effectively to improving vitamin A and mineral intakes, including iron and zinc. Raw amaranth leaves alone contain 2.46 grams of protein, 2.32 mg of iron, 0.90 mg of zinc, 146 µg of vitamin A RAE and 23 Kcal of energy per 100 grams of sample [7] . Similarly, raw orange fleshed sweet potato contains 1.57 grams of protein, 0.61 mg of iron, 0.30 mg of zinc, 709 µg of vitamin A RAE and 86 Kcal of energy per 100 grams of sample; and raw pumpkin contains 1.00 grams of protein, 0.80 mg of iron, 0.32 mg of zinc, 426 µg of vitamin A RAE and 26 Kcal of energy per 100 grams of sample [7] . These vegetables can be blended with legumes and/or cereal crops (including grain amaranth and soybean) in food formulations targeted for children so as to improve the nutrient and energy densities. For example, raw 100 grams portion of grain amaranth contains 13.5 grams of protein, 7.61 mg of iron, 2.87 mg of zinc, 2 µg of vitamin A RAE and 371 Kcal of energy [7] and this grain has been used for feeding severely malnourished children [8] while raw mature soybeans contain 36.5 grams of protein, 15.7 mg of iron, 4.9 mg of zinc, and 446 Kcal of energy per 100 grams of sample [7] .

The aim of this work was therefore to evaluate the acceptability, nutritional quality and estimated contribution of vegetable enriched products to the RDA of school age children (5 to 13 years).

2. Materials and Methods2.1. Raw Materials, Source and Justifications for Inclusion

The raw materials used were purchased within Kampala, Uganda. Red and green amaranth (A. cruentus and A. lividus; respectively) leaves, soybeans and pumpkin (Cucurbita maxima) were purchased from fresh food markets in Kampala. Grain amaranth flour (golden amaranth) was obtained from Nutreal Limited in Kampala, while orange fleshed sweet potato (OFSP) (Ejimula) was procured from a farmer in Bombo; about 20 kilometers from Kampala. The raw materials were selected based on their content of nutrients of public health concern which include iron, vitamin A and Zinc; as well as their protein and energy content. Besides nutritional endowment; red and green amaranth leaves were selected because they are the most abundant and commonly consumed leafy vegetables in Kampala. On the contrary, OFSP and pumpkin were selected so as to formulate products that can lead to popularization of their use as they are locally grown but their consumption is generally limited.

The vegetables (red and green amaranth leaves, pumpkin mesocarp and OFSP) are generally rich in micronutrients especially vitamin A [6] but are not quite high in iron, zinc and protein so they were blended with soybean which also contains monounsaturated oil that helps in the absorption of fat soluble vitamin A. Grain amaranth (GA) was added as it has high content of iron, energy and starch which is necessary for porridge and soup consistency. GA was also selected to promote its utilization and consumption.

2.2. Preparation and Processing of the Raw Materials2.2.1. Red and Green Amaranth Leaves

Preparation

The processing method used was similar to that of [9] . The fresh amaranth leaves were sorted and graded to remove damaged and discolored ones, washed thoroughly and rinsed with potable water. The washed vegetables were pretreated with sodium metabisulphite solution at 2 grams/litre (0.2 w/v) for 1 minute to avoid browning then spread on a clean tray with foil and dried at temperature of 65˚C for 12 hours using a cabinet dryer (B. Master SR 2046, TAURO Italy) until brittle.

Processing

The dried vegetable leaves were milled into flour using a locally made hammer millin the laboratory, sieved through a 50 - 100 mesh screen, packed into a clean dry bag, sealed and kept in the cold room at 2˚C until use.

2.2.2. Soybeans

Preparation

Soybeans were processed according to the method of [10] with some modifications. Once purchased, it was sorted to remove damaged ones, stones and dirt.

Processing

Soybeans were soaked for 8 hours, washed several times with water, dehulled manually, blanched at 90˚C [11] for 10 minutes and dried at 65˚C for 24 hours using cabinet dryer (B. Master SR 2046, TAURO, Italy). The dried soybeans were roasted using infrared food oven (GU-6 A80037, Malaysia) at 180˚C for 20 minutes, cooled, milled into flour using a locally made hammer mill, packed into a clean cellophane bag and refrigerated at 2˚C until use.

2.2.3. Orange Fleshed Sweet Potato (OFSP)

Preparation

The processing method used was similar to that reported by [12] with modifications. The OFSP were sorted to remove damaged ones and dirt, peeled manually, washed several times with potable water and sliced using a locally made chipping machine. The chips, were dipped in aqueous 0.2% (w/v) sodium metabisulphite solution for 1 minute to avoid enzymatic browning during drying and storage and then dried using cabinet dryer (B. Master SR 2046, TAURO Italy) at a temperature of 65˚C for 7 hours.

Processing

The dried flakes were milled into flour using a locally made hammer mill, packed into a plastic bag and stored in the cold room at 2˚C until use.

2.2.4. Pumpkin

Preparation

The processing method for pumpkin was similar to the method used by [13] . The pumpkins were manually peeled with a knife so as to remove the outer layer. The seeds and peel were discarded while the flesh was chipped with a locally made chipping machine, soaked in 0.2% (w/v) sodium metabisulphate for 1 minute to avoid enzymatic browning and dried using cabinet dryer (B. Master SR 2046, TAURO Italy) at 70˚C for 15 hours [14] .

Processing

The dried pumpkin chips were milled into flour using a locally made hammer mill, packed into a plastic bag and stored in a cold room at 2˚C until use.

2.3. Blending of the Flours

Concept 4 Creative Software [15] was used to formulate the blends that would contribute to vitamin A, iron, zinc, protein and energy requirements of children aged 5 to 13 years. The reference nutrient contents of the supposed raw materials used in this study (in flour form) were derived from combination of literatures; afterwards they were run through the software to generate those nutrient levels (Table 1). The orange fleshed sweet potato (OFSP), pumpkin, red amaranth

Nutrient compositions and energy content (per 100 g) of the orange fleshed sweet potato (OFSP) composite and red amaranth composite as predicted by concept 4 software
Composite name (abbreviations)Vegetables (10%)Soy bean flour (%)Grain Amaranth flour (%)Energy (Kcal)Protein (g)Vitamin A (mcg)Fe (mg)Zinc (mg)
OFSP (OSG)OFSP flour4050467.916.5192.44.72.9
Red amaranth (RSG)Red amaranth leaves flour4050457.219.2376.07.15.4

OSG = Orange fleshed sweet potato + soybean + grain amaranth, RSG = Red amaranth leaves+ soybean+ grain amaranth.

leaves and green amaranth leaves were incorporated at 10% level individually to soybean (40%) and grain amaranth (50%) which initially resulted to four formulations (OFSP composite OSG, Pumpkin composite PSG, Red amaranth composite RSG and Green amaranth composite GSG); respectively (Table 1). The four formulations were screened for products including porridge, soup and snacks-chapattis.

2.4. Preparation of the Foods Incorporating the Vegetable Enriched Composite Flours

Porridges, soups and snacks-chapattis incorporating the vegetable enriched composite flours were prepared. The choice of these products was influenced by their likelihood to be adopted as similar foods are commonly given to school age children. For preparation of chapattis, 30% of the vegetable-enriched composite flours were added to 70% of wheat flour [16] and other ingredients (Table 2). The ingredients were thoroughly mixed by hand to make dough. Portions of 65 grams were flattened using a roller pin (to a thickness of about 0.2 cm and diameter of 18 cm) then shallow fried for about 3 minutes.

For soup preparation, all the dry spice ingredients (22 grams) were mixed with 78 grams of each of the composite flours (Table 3). The soup mixtures (100

Recipe used for preparation of vegetable enriched chapattis
IngredientsProportions
Wheat flour (grams)700
Composite flours (grams)300
Water (ml)500
Grated carrot (grams)78
Sunflower oil (sun seed, ml)65
Grated onions (grams)43
Table salt (grams)16

Adapted from [16] [17] with modifications.

Recipe used for preparation of vegetable enriched soup
IngredientsProportions
Composite flours (grams)78.0
Water (ml)800.0
Sun flower oil (sun seed, ml)10.0
Table salt (grams)8.0
Dried tomato (grams)5.0
Dried grated onions (grams)2.5
Curry powder (grams)2.0
Dried carrot (gram)1.0
Spices (pilau powder, gram)1.0
Dried green pepper (gram)0.5

grams) were cooked with 800 ml of water and 10 ml of sunflower vegetable oil for 10 minutes. For porridge preparation (Table 4), the flour rates (FR) used were those determined to result in drinkable viscosity range (2500 - 3000 cP) [18] [19] for children. The porridges were cooked for 10 minutes and 30 grams of sugar were added per litre of porridge.

Based on the screening result, it was found that the two most accepted formulations were: OFSP composite, denoted as OSG (which comprised of 10% OFSP, 40% soybean and 50% grain amaranth) for porridge and chapattis and; red amaranth composite, denoted as RSG (which comprised of 10% red amaranth leaves, 40% soybean and 50% grain amaranth) for soup. Therefore these two formulations were adopted and used in this study. These two formulations were evaluated for sensory acceptability, nutritional quality and estimated contribution of the products to the vitamin A, iron, zinc, protein and energy requirements of children aged 5 - 13 years.

2.5. Acceptability Test of Vegetable Enriched Products in Comparison to Commercial Products

Test for acceptability was done with the: OFSP composite for porridge and chapatti preparations; red amaranth composite for soup preparation in comparison to that of commercial products. The commercial products used in this study were maize porridge, chapattis made from 100% refined wheat flour and refined wheat flour based composite soup. These commercial products (maize porridge and 100% wheat flour chapattis) were selected because they are commonly consumed by both school children and adults in Uganda. Refined wheat flour based composite soup flour was selected as one of the few processed soup flours on the shelf and also according to sellers in supermarkets; it was among the most purchased soup flour in Kampala. The flour rate (FR) and viscosity of OFSP composite and maize porridges were determined (to meet the standard porridge viscosity requirement 2500 - 3000 cP for children [18] [19] and the porridge was prepared using the FR derived. The commercial wheat flour composite soup (which contains other soup ingredients in the sachet) was prepared according to the manufacturer’s specification that recommends mixing 60 grams (6%) of soup flour in 850 ml of water and cooking for 6 minutes while that of red amaranth composite soup was prepared by mixing 100 grams (of flour and soup mixtures) in 800 ml of water (Table 3). Viscosities (cP) determination of the commercial products (maize porridge and wheat flour composite soup) was done with the same specifications used for the viscosity determination of the actual

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