Extruded Baru Flour Addition (Dipteryx alata Vog.) in Cookie ...

Extruded Baru Flour Addition (Dipteryx alata Vog.) in Cookie Formulations: Effect on Consumer’s Acceptability D.G.C. Freitas, C.Y. Takeiti, R.L.O. Godoy, J.L.R. Ascheri and C.W.P. Carvalho Embrapa Food Technology Avenida das Américas 29501 CEP 23020-470 Rio de Janeiro/RJ Brazil

P.L.M. Souza, A.E.C. Ribeiro and D.P.R. Ascheri State University of Goiás BR 153 3105, Fazenda Barreiro do Meio CEP 75132-903 Anápolis/GO Brazil

Keywords: baru pulp flour, consumers’ acceptability, thermoplastic extrusion, cookie, physico-chemical properties Abstract The pulp of baru (Dipteryx alata Vog.), a species of the Fabaceae family that occurs in the Brazilian savannah, can be exploited for its high fiber, minerals and proteins content, in addition to its unique flavor. In order to increase the demand for nutritional foods and to assess new sources of food, this study investigated the effect of baru pulp flour addition during formulation of cookies on consumers’ acceptability. Mixture of baru pulp flour (BPF) and rice flour (RF) in a proportion of 30:70 (w/w, d.b.) was extruded in a single lab extruder resulting in baru-rice pregelatinized flour (BRF). Five cookies samples (0, 10, 20, 30 and 40% BRF) were evaluated on overall liking, texture and flavor acceptability by consumers. According to overall acceptability scores, consumers were classified into different clusters using the Euclidean distances and Ward’s aggregation method. The Principal Component Analysis (PCA) identified uniform or atypical groups of observations. The BPF sugar content and functional properties of raw and extruded mixtures of BPF and RF (30:70, 40:60, w/w) were also determined. BPF presented high sugar content (30.3% sucrose, 22.8% fructose and 6.7% glucose). In general, consumers preferred the cookie formulated with 10% of BF, mostly due to changes in its flavor. The maximum BRF percentage to be added in cookie formulation in order to avoid a loss in consumers’ acceptability was estimated considering the first significant difference and corresponded to 12.82%. Nevertheless, different clusters of consumers could be identified with different overall liking scores and characteristics of gender, income and age. The PCA analysis confirmed the preference of cookies with 10% BRF, but the cookies with 20, 30 and 40% BRF had a good acceptance by a large group of consumers. These findings indicate the potential use of the extruded mixture with BPF to improve the nutritional quality of foods. INTRODUCTION The baru (Dipteryx alata Vog.) is a species of the Fabaceae family (LeguminosaePapilionoideae) that occurs in the most fertile soils of the Brazilian savannah known as Cerrado vegetation, in the Midwest of Brazil with altitude higher than 800 m (Correa et al., 2008). Externally, the baru fruit has a brown colour and present an oblong appearance measuring 4-5 cm in length. The pulp of baru can be exploited for its high fiber, minerals and proteins content, and in addition for its exclusive flavor. Each fruit has a unique seed that presents brown colour and ellipsoidal shape (Almeida et al., 1991). Both pulp and seeds of baru can be used in food formulations such as cookies, cakes, sorbets, ice cream, candies and chocolates. Proximate composition (expressed in dry basis) of baru pulp revealed 5.6% proteins, 3.4% lipids, 3% ash, 20.4% total sugar, 38.0% starch and 29.5% dietary fibers, including 1.3% soluble fibers and 28.2% of an insoluble fraction (Togashi and Sgarbieri, 1994). The high contents of starch and fiber in the baru pulp are very Proc. IIIrd IS on Human Health Effects of Fruits and Vegetables Eds.: B. Patil et al. Acta Hort. 1040, ISHS 2014

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interesting constituents to produce extruded products. Traditionally, extrudates are solely rich in carbohydrates. Extrusion process is interesting, since it is widely used to incorporate hard-to-cook seeds or insoluble flours into cereals, which are then used to produce precooked flours, instant food and expanded snacks. These extruded products have advantages in terms of their sensory characteristics (texture, flavour, smell and colour), physical characteristics (paste viscosity features) and nutritional properties (high protein content and balanced amino acid profile or fiber addition) (Cheyne et al., 2005). However, extruded rice-based flour supplies dietary energy source are low in dietary fiber. The incorporation of fiber into flours reduces the quality of extruded products conventionally elaborated, but improves functional characteristics. In addition the increase of fiber content can replace part of the calories provided by pre-gelatinized flours. Baru pulp flour provides dietary fiber and minerals and its application into extruded foods is not found in the literature. In order to increase the demand for foods with high content of dietary fiber, and the need for new sources of these nutrients, this study investigated the effect on consumers’ acceptability of baru-rice gelatinized flour addition in formulating cookies. MATERIALS AND METHODS Baru Pulp Flour (BPF) Elaboration Baru fruits (D. alata) were collected from Brazilian Cerrado, in the mid-western of Brazil. Ripe fruits were selected and washed in running water. Afterwards, neutral detergent and sodium hypochlorite solution (200 mg L-1) were used to sanitize the fruits. The pulp was separated from the seeds, ground in a hammer Mill and dehydrated in an oven (Marconi, MA-035, São Paulo, Brasil) until a constant weight was reached at 40°C. This material was packed in plastic bags, sealed and stored at 5°C. BPF Proximate Composition and Sugar Analysis The proximate composition of BPF was determined according to AOAC (2000) and crude fiber content as described by Brasil (2005). Glucose, fructose and sucrose contents of BPF were determined according to Macrae (1998) using a Reverse Phase High Performance Liquid Chromatography (RP-HPLC) system with external standardization. Baru-Rice Pre-Gelatinized Flour (BRF) Preparation Commercial polished rice was purchased in a local market at Rio de Janeiro City (Brazil). Rice was ground using a knife-hammer mill (TREU, Rio de Janeiro, Brazil) equipped with 1 mm opening sieve, which produces a rice flour (RF) with an average particle size of 300 µm. Mixtures of BPF:RF (30:70, 40:60 and 0:100, w/w, d.b.) were prepared conditioning at 16% (v/w) of moisture during 24 h under refrigeration. Extrusion was performed on a single screw extruder (Brabender, model 19/20DN, Duisburg, Germany) operated at 160 rpm, 3:1 barrel length to diameter ratio, 3 mm round die and 4 kg/h feed rate. The expanded extrudates were placed in a convection oven (Fabbe-Primar, São Paulo, Brazil) at 70°C setting to dry overnight. Dried extrudates were ground in a disk mill (Perten Instruments AB, model 3100, Huddinge, Sweden) in order to obtain baru-rice gelatinized flour (BRF30 and BRF40). The BRF were then sieved for 2 min using a plan sifter with aperture sizes of 1.40; 1.18; 0.85; 0.71; 0.50; 0.42 and 0.30 mm (Ro-Tap, RX 29-10, Mentor, USA). BRF Quality A Rapid Visco Analyser model 4 (RVA, Newport Scientific Pty Ltd., Warriewood, NSW, Australia) was used to measure the apparent viscosity of samples as a function of temperature. BRF was sieved and samples, sifted between 106 and 250 µm, were collected in order to conduct paste viscosity runs in duplicate. The readings from the 90

paste curve generated were maximum viscosity peak at 25°C (MV25), minimum viscosity after heating (MV95), breakdown (MV95-MV25), final viscosity (FV) and set back viscosity (FV-MV95). Water absorption (WAI) and water solubility indexes were carried out according to the methodology described by Anderson et al. (1969) with modifications. The absolute density and total pore volume were determined by a pycnometry using an Automatic Gas Pycnometer (mod. AccuPyc 1330, Micromeritics, Norcross, USA) and samples were previously dried in an oven at 105°C overnight. BRF Cookie Formulations and Making Procedures The formulations of cookies were made with: starch (100 g), refined sugar (350 g), hydrogenated vegetable fat (300 g), vanilla (20 ml), milk powder (50 g), bicarbonate of soda (15 g), water (100 ml) and BRF addition of 10, 20, 30 and 40% in substitution to wheat flour (900 g). All ingredients were purchased in a local market in Rio de Janeiro city, except BRF30 that was chosen due to paste viscosity and WAI/WSI features. The ingredients were weighed and mixed in a laboratory planetary mixer in order to obtain smooth and homogeneous dough and then, divided in portions of 10 g. The dough was sheeted to a thickness of 5 mm manually with rolling pin and shaped using a 3 cm circular cutter. Cookies were baked at 200°C for 15 min in a convective oven (MATADOR, WP Bakerygroup, Rietberg, Germany), cooled until room temperature and stored hermetically in a plastic recipient. Consumer Evaluation of BRF Cookie Formulations The consumer test was conducted in the Embrapa Food Technology, in Rio de Janeiro, Brazil. Consumers (120) were recruited from students and workers from administrative and technical staff of Embrapa. Consumers were selected according to their liking and consumption frequency of this kind of products. They were 53% women and 47% men, and their ages ranged between 18 and 55 years. Consumers were given the information about the baru flour and its nutritional properties before the evaluation. Five cookies samples were evaluated following the procedure designed to reduce the effects of order of presentation and first order carry-over effects. Consumers evaluated overall liking, texture and flavor acceptability on 9-points hedonic scales: 1-disliked extremely; 5-neither liked nor disliked; 9-liked extremely. Consumers also were asked about their purchase intention on a 7-points structured scale: 1-certainly not buy; 4-neither buy not buy; 7-certainly buy. The samples were served in units with water between each other. The session was conducted in individual’s booths, which were illuminated by white light. Data Analyses Analysis of variance (ANOVA) for the effect of BPF addition on BRF properties was accomplished using the software XlStat (2008). Significant differences among treatment least-squares means were separated by Tukey’s or Fisher’s test at p