Tropical Science Trop. Sci. 2007, 47(1), 52 56 Published online in Wiley InterScience (www.interscience.wiley.com).196 Development of a new tapioca product with tropical fruit pulp and soy extract Edy Sousa de Brito*, Deborah dos Santos Garruti and Daniele Sales Silva Embrapa Agroindústria Tropical, R. Dra. Sara Mesquita, 2270, Pici, Fortaleza, Ceará, CEP 60511 110, Brazil. *To whom correspondence should be addressed (edy@cnpat.embrapa.br) Abstract Tapioca is a traditional product with great acceptability, especially in Brazil. As a starch-based food, its nutritional quality is limited to carbohydrates. The aim of this work was to evaluate the contribution of tropical fruit pulps and soy extract to tapioca s nutritional and sensory characteristics. The products were formulated with dried tapioca starch (63%) supplemented by acerola or mango fruit pulps or by soy extract in selected combinations (37%). The mixtures were homogenised and roasted for starch gelatinisation. The fi nal product was submitted to vitamin C and protein determinations and sensory analysis (appearance, fl avour, texture and overall acceptance). Vitamin C content of the acerola tapioca products was signifi cantly increased. Protein content was increased by supplementation with soy but the absolute levels were still quite low. Acceptability by sensory attributes of formulated tapiocas was similar to, or in some cases higher than, the traditional product. Copyright 2007 John Wiley & Sons, Ltd. Key words: food enrichment, tapioca, soy, fruit pulp, tropical fruits Introduction Food fortification is defined by the Codex Alimentarius as... the addition of one or more essential nutrients to a food, whether or not it is normally contained in the food, for the purpose of preventing or correcting a demonstrated deficiency of one or more nutrients in the population or specific population groups.... There are technologies available for vitamin C fortification of fruit juices, fruit juice drinks and related beverages, dairy products and some breakfast cereals. Besides its antioxidant capacity, vitamin C in foods is known to improve iron bioavailability (Henriques and Cozzolino 2005). High moisture content (>7%) in the presence of oxygen is known to have an adverse effect on the stability of vitamin C in cereals. There is a need to develop more stable vitamin C compounds and evaluate their use for fortification of a range of products (FAO 1996). Protein-energy malnutrition is a common serious nutritional problem in almost all countries of Asia, Africa, Latin America and the Near East (Latham 1997). Cassava, widely consumed in tropical countries, is a good source of starch. Tapioca is a pancake-like delicacy made from gelatinisation of wet cassava starch by roasting it over a hot plate. It is dipped in
Tapioca with fruit pulp and soy extract 53 a solution of condensed or coconut milk in plain milk, and immediately consumed. Tapioca is largely consumed and appreciated in Brazil s northeast. Cassava flour fortification with iron and bioproteins was considered as a promising technology by Metri et al. (2003) and Tuma et al. (2003). Thus, tapioca-based products could be a good vehicle for nutritional improvement. The aim of this work was to develop tapioca products and evaluate the potential use of acerola or mango pulp and soy extract to improve tapioca s nutritional quality, in terms of vitamin C and protein contents, without impairing its sensory acceptance. Materials and methods Dry tapioca starch, acerola and mango pulps, and soy extract were purchased at a local market (Fortaleza, Ceará, Brazil). The soy extract was prepared as milk at 20% concentration (w/v) in water. Tapioca starch (63%) was prepared in five formulations with 37% of: water (traditional tapioca product, as the control); acerola pulp (Malpighia emarginata); acerola plus mango pulps (1 : 1 w/w); soy extract; or acerola pulp plus soy extract (1 : 1 w/w). The mixtures were moulded into aluminium rings (8.5 cm diameter 2 cm high, i.e. holding 110 115 cm 3 ) and roasted on an aluminium plate (1 cm thick) placed on a burner stove until starch gelatinisation and case hardening occurred (about 3 min). After roasting, the product was taken out of the mould for immediate consumption. This round product is usually known as a tapioca. For each treatment, ten tapiocas were analysed in triplicate. The samples were homogenised and the appropriate amount weighed for chemical analysis. Vitamin C was determined by titration with 2,6-dichlorophenol-indophenol (Pearson 1976). Protein concentration was determined by the Kjeldahl procedure (IAL 1985). Forty-five consumers (ranging from 20 to 40 years old, 70% female) were recruited as judges from Embrapa s staff and trainees. The individuals were familiar with tapioca and consumed it normally at least once a week. Judges were asked to rate each sample in terms of overall acceptance, appearance, flavour and texture, using a 9-point hedonic scale ranging from like extremely to dislike extremely (Ferreira 2000). Samples, consisting of a quarter of a round tapioca, were presented to the judges either undipped or after dipping into a mixture of condensed milk and whole milk (1 : 1) for 5 s. A randomised complete block design was used, with the judges treated as the block factor, balanced for order and carry-over effects. Mineral water was provided as a palate cleanser between samples. All evaluations were conducted at 22 C under day-light white lights in individual booths. Analysis of variance of sensory data was performed using a General Linear Model procedure for each attribute. The model consisted of judges, formulations (F), presentation (P) and the interaction between F and P. Means were compared using the REGWQ multiplerange test. All statistical analyses were performed using the SAS software program (Windows version 4.10, 1998).
54 Edy Sousa de Brito et al. Results and discussion The vitamin C and protein contents of each product are shown in Table 1. In traditional tapioca, made with moistened tapioca starch, neither vitamin C nor protein could be detected. By contrast, the products formulated with fruit pulps reached a good level of vitamin C (in spite of the roasting process), and the vitamin C concentration in the acerola product was significantly higher than in the acerola-mango and acerola-soy products. Such results are clearly due to the high vitamin C level usually found in acerola fruits, e.g. Musser et al. (2004) obtained levels of 1067 1846 mg 100 g 1 of pulp. Since a tapioca portion weighs approximately 100 g, any of the three acerola-supplemented tapiocas could provide more vitamin C than the recommended dietary allowance of 90 mg day 1 for an adult male (Institute of Medicine 2000). Tapiocas supplemented with soy extract had a protein concentration of 2.8 g 100 g 1, significantly higher than that of the tapiocas with acerola plus soy, but further development is needed to achieve higher protein contents. Sensory analysis revealed good levels of acceptance for all sensory attributes, and showed highly significant effects of products (formulations) and presentation (whether dipped in milk or not). No significant interaction was found between formulation and presentation (Table 2). Tapiocas presented after dipping in condensed milk always scored higher acceptance levels than samples not dipped in milk (Table 3) and these differences were significant in all Table 1. Vitamin C and protein contents (mean ± standard deviation) of different tapioca formulations Tapioca formulation Vitamin C (mg 100 g 1 ) Protein (g 100 g 1 ) Traditional nd nd Acerola 452.3 ± 32.3 a nd Acerola + mango 256.0 ± 7.8 b nd Soy nd 2.8 ± 0.1 a Acerola + soy 224.8 ± 13.9 b 1.4 ± 0.2 b Means in the same column with different letters are significantly different at p < 0.05. nd = not detected. Table 2. Analysis of variance of the effects of formulations and presentation on the sensory acceptance of tapioca Source of Appearance Flavour Texture Overall acceptance Variation F-ratio F-ratio F-ratio F-ratio Judges 2.00** 1.95** 2.88** 2.20** Formulations (F) 7.96** 9.50** 9.03** 8.01** Presentation (P) 61.26** 196.87** 156.72** 193.49** F P 1.13 ns 0.79 ns 1.97 ns 0.99 ns ** Highly significant effect at p < 0.01. ns = not significant.
Tapioca with fruit pulp and soy extract 55 Table 3. Sensory acceptance means (9-point hedonic scale) for attributes of different tapioca formulations with or without dipping in milk solution Attribute and formulation With milk Without milk Appearance Traditional 7.63 a,b 6.37 a,b Soy 8.02 a 6.90 a Acerola 7.18 b,c 5.52 b Acerola + mango 6.57 c 5.98 b Acerola + soy 7.36 b,c 6.04 a,b Flavour Traditional 7.71 a,b 5.57 a,b Soy 8.19 a 6.46 a Acerola 7.50 b 4.88 b Acerola + mango 7.12 b 4.79 b Acerola + soy 7.73 a,b 5.69 a,b Texture Traditional 7.06 b 4.03 b Soy 8.02 a 6.14 a Acerola 7.39 a,b 5.52 a Acerola + mango 6.95 b 5.21 a Acerola + soy 7.38 a,b 5.51 a Overall acceptance Traditional 7.51 a 5.09 b Soy 8.07 a 6.49 a Acerola 7.51 a 5.09 b Acerola + mango 7.04 a 5.12 b Acerola + soy 7.56 a 5.58 b Means for each attribute in the same column with the same letters are not significantly different at p < 0.05. cases except the flavour of traditional tapiocas. Without milk, there was no significant difference in appearance and flavour between the traditional product and any of the formulated tapiocas, whereas the formulated tapiocas scored significantly higher hedonic values for texture than the traditional one in the absence of milk. Other significant differences in sensory attribute scores between the tapioca formulations are indicated by the results of the multiplerange tests shown in Table 3. Soy tapioca showed a significantly higher value for overall acceptance among the tapioca products presented without condensed milk, corresponding to a category between like slightly and like moderately. The addition of milk reduced the differences between formulations, but increased considerably the acceptance of all products, which reached values between the like moderately and like very much categories. This initial study indicated that the developed tapioca products had good sensory acceptance and improved nutritional qualities. In particular, the product with acerola yielded a high vitamin C content.
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