Introduction: Functional food represents food that can be healthier than the usual ingredients in the food (Majzoobi et al., 2013). Cereal products are the main source of calories and energy in the diet. Among them, biscuits are popular because of their lower moisture, higher shelf life, relatively low cost and a wide variety of flavors (Anton et al., 2009; Hager et al., 2011). In recent years, there has been many of research on the effect of adding various compounds to cereal products such as mango peel powder (Ajila. Partners 2008), date juice (Majzoubi et al. 2016), lecithin in biscuits (facts and angles 2017), vegetable and fruit wastes (Sharboa et al. 2013), potato peel powder in cakes (Jedo et al., 2017) and pineapple powder in bread (Solani et al. 2014) has been done to improve the nutritional properties of the products. Oak fruit contains nutrients such as magnesium, calcium, minerals, fiber and biologically active compounds with antioxidant properties and tannins that make it practical and functional‌ (Ozkan and Baiko 2005). Acorn also has useful properties including disinfectant; eliminate anemia, vascular swelling reduction and more. Recently, studies on the use of acorn flour in Barbari bread (Majzoubi et al. 2013), sponge cake (Rumi et al. 2014), and cupcake (Roshani and Naghipour 2018) acorn flour with soy flour in cake (Sorouki et al. 2013) And baguette bread (Hojjati and Atash Saz 2013) was made to enrich cereal products. Triticale is a new plant from hybrid between wheat and rye (Nassimento 2003) that contains high amounts of protein, minerals, vitamins, and high phenolic content compared to other cereal especially wheat, as well as it has rapid growth and production capacity in poor and low-yielding lands(Serena et al. 2004). This flour is more suitable for making bulgur bread, thin and flat breads and extruded products (Farash et al. 2016). Triticale flour has been used to enrich products such as crackers (Cabreilla et al. 2003), biscuits (Blanco et al. 2017) and cookies (Alberto et al. 2000). In recent years, extensive efforts have been made to improve and enrich cereal products; Therefore, according to the society's need to improve the nutritional value of foods, the purpose of this study is to investigate the possibility of replacing wheat flour with acorn flour and triticale flour in the production of biscuits and to study the physical, chemical, textural and sensory properties of the product.
Purpose: Acorn flour and Triticale flour have been considered because of their good nutritional properties and can be used to enrich cereal products; so the aim of this study was to produce biscuits enriched with acorn flour and Triticale flour with texture quality and suitable nutrition.
Methods: In this study, the effect of replacing acorn flour and Triticale flour at levels of 0-30% with wheat flour on the physical, chemical, texture and sensory properties of biscuits was investigated with using the mixture design based on D-optimal. For this purpose acorn fruit was harvested from the forested areas of West Azerbaijan in early autumn and after separating the outer hard layers and the second layer (pair), dried at room temperature for 72 hours and then the acorn kernel was milled and after sieving, it was kept in thick polyethylene bags in the refrigerator until consumption.
Formulation of control biscuit dough was included 200 grams of wheat flour, 100 grams of granulated sugar, 70 grams of margarine, 2-3 grams of vanilla, 1-2 grams of baking powder and 1 egg. Replacement of acorn flour and triticale flour at the level of 0-30% with wheat flour was based on mixture design. To make the biscuit, all the ingredients were well mixed after weighing. The resulting dough was rested for 15 minutes after kneading and uniformity of texture. After this time, the doughs were spread with a rolling to 2-3 mm of thickness and after molding (with a diameter of 5 cm), it was baked in an industrial oven at 160‌oC for 12 minutes. After leaving the oven and cooling, the samples were thermally packaged in polyethylene bags and kept at room temperature until the tests (Caponio et al. 2007). Biscuits were characterized for moisture, fat, protein, ash, carbohydrates, calories, water activity, antioxidants capacity, density, spread ratio, and colorimetric indices, textural, and sensory properties.
Results: Triticale is a good alternative to other cereals, especially wheat, due to its good nutritional composition such as protein, minerals, vitamins, and high fiber content. Also, the improvement effect of triticale flour is due to its high alpha-amylase activity, which compensates for the low activity of alpha-amylase in wheat flour. acorn flours On the one hand, acorn flour is rich of fiber and minerals, so adding acorn flour to biscuits could improve maintenance of moisture, increase nutritional value, and improve the texture properties of the product. Therefore, this study was designed to evaluate the effect of replacing acorn flour and triticale flour on the physico-chemical, textural and sensory properties of biscuits.The results showed that moisture content and water activity of the samples containing triticale and significantly increased‌(P‌<0.05) due to the high mineral and fiber content of triticale flour and acorn flour compared to wheat flour, which absorbs more water and thus increases moisture. The fat content of the samples significantly increased with replacement of acorn flour due to the high fat content of acorn flour (9%) compared to other consumed flours. Also, with replacement of acorn flour, the amount of carbohydrate and calorie of the samples decreased (P≤0.05). With replacement of acorn flour, the spread ratio of the samples increased which is due to the decrease of gluten in wheat flour and the inability to retain gas and water vapor in the biscuit and thus reduce the thickness of the biscuit. The replacement of triticale flour with wheat flour had no significant effect on spread ratio. With replacement of acorn flour, the antioxidant capacity of the samples significantly increased that due to the presence of alpha and gamma-tocopherols, gallic acid, tannins and phenolic substances in acorn fruit. Interaction effect of acorn-triticale flours was significant on textural parameters. By addition of triticale flour up to 10% (at low levels of acorn flour), the required force and energy for penetration of the samples increased, but with more substitution, these properties decreased. Addition of acorn flour at high levels of triticale led to decrease of firmness and energy. The replacement of triticale and acorn flours had no significant effect on protein‌, ash, density and b* value of samples (P>0.05). Also, overall acceptance in sensory evaluation decreased with the replacement of triticale and acorn flour, but all samples had acceptable grade (0.74) in the range of 0-1.
Conclusion: The results of optimization showed that the biscuits with high desirability in terms of textural and sensory properties can be developed by the substitution of 15% triticale and 15% acorn flour together. In general, according to the results replacement of wheat flour with acorn and triticale flours in biscuit formulation, let to producing functional biscuit with low calorie and high nutritional value.