The Use of Waxy Starch and Guar Gum in Total Substitution of Vegetable Oil in Extruded Snack Aromatization

Abstract

Vegetable oil is used by the extruded snacks industries to fixate aromas and salt in proportions between 10 and 20%. Consumers have restricted the consumption of these products due to the high content of lipids and low nutritional value. In order to obtain a low-fat option, this work aimed to reduce the lipids content of extruded snacks by replacing vegetable oil with waxy maize starch and guar gum. The snacks were manufactured in an INBRA RX50 mono screw extruder using corn grits as a base ingredient. The snacks were flavoured with five coatings formulations varying the concentration of waxy maize starch (1-4%) and guar gum (0.25-1.0%). A total of 15% solution by weight of snacks was applied, and the control treatment consisted in vegetable oil only. The products were evaluated for moisture content, total lipids, radial expansion index, specific volume, apparent density, retraction index, instrumental hardness (Texture Analyzer TA-XT Plus - Stable Micro Systems) and sensory evaluation with 100 non-trained panellists. Moisture and lipid contents were determined in 0 and 30 days of storage. Temperatures of 65 °C were required for waxy starch solution preparation, lowering the temperature to 50°C for the formulations with the addition of guar gum. The results indicated that it was possible to replace the vegetable oil by waxy maize starch and guar gum in the aromatisation of the snacks, as the products presented similar moisture content, specific volume, apparent density, retraction index, sensory acceptance and instrumental hardness (p > 0.05). Furthermore, the products presented a reduction of 11-13% in the lipid content. The addition of waxy maize as the only substitute would be recommended, because of the quality characteristics of the products and the absence of significant influence with the addition of guar gum. The snacks produced in the present study would be a healthier option to the consumer.