Physical properties of biscuit
Studies of physical properties are very important for baked products. Since consumer choice and preferences for various bakery products are expanding, the food industry increasingly depends upon ingredient which imparts good functional properties along with nutritional qualities. The analysis on physical characteristics of developed rice based biscuits is presented in Table 3.
Diameter
The diameter of rice based biscuits ranged from 3.80 to 3.84 cm. In control biscuit diameter was 3.84 cm and diameter reduced to 3.80 cm in T
2 , 3.81 cm in T
3, 3.80 cm in T
4, 3.81 cm in T
5. The reduction in diameter may be due to high fibre content of developed biscuits which absorbs water and thereby reduce in expansion of diameter of the biscuits as compared to control biscuits
(Baljeet et al., 2010), however reduction of diameter of developed gluten free biscuits was found to be statistically non significant at P<0.05.
Baljeet et al., (2010) reported that expansion in diameter decreases due to addition of buckwheat flour in biscuit which may be due to increased fibre content in biscuits.
Thickness
From Table 3 it is evident that the thickness of control biscuit was much higher (0.87cm) in comparison to all other treatments. The thickness of other treatments ranged from 0.76 to 0.79 cm. Different levels of incorporation of rice flours shows statistically significant effect on the thickness. It might be contributed by the fibre in the biscuit formulation which decreased the thickness of biscuit. Studies observed the reduced expansion of thickness with addition of fibre containing ingredients in developed biscuits.
(Mridula et al., (2009); Mridula 2011). Several studies also indicate that crude fibre of the biscuit formulations reduces the thickness development during cooking (
Brennam and Samyue, 2004;
Mridula et al., 2007).
Weight
The weight of control biscuit was recorded to be 6.1g which was found lower than all other treatments. Weight of biscuits of other treatments ranged from 7.06 g to 8.0 g. There is a nominal increase in the weight of other treatments in comparison to weights of the samples T
2 and T
4, T
3 and T
5 was observed.
Man et al., (2014) reported that biscuits developed by mixing of different flours with rice flour increases the weight which ranged between 8.4g to 8.2g in T
1 – 33.33:33.33:33.33 ; T
2 – 32:42:26; T
3 – 30:30:40 ; T
4 – 26:37:37 of composite flour (maize flour, rice flour, soybean flour respectively).
Spread ratio
The changes in diameter and thickness of biscuits are reflected in the spread ratio of biscuits. It is found to be increased on incorporation of composite flours when compared to control biscuit. Sample T
2, T
3, T
4 and T
5 has no significant difference among the treatments which ranged from 4.80 cm to 5.0 cm. The increasement in spread ratio of the biscuits in comparison to control biscuit is significant by different at P<0.05. The increase in spread ratio might be due to addition of soyabean flour and buckwheat flour which are rich in protein and fibre which has high water binding power. Increasement also may be due to decrease in thickness of biscuit developed.
Giwa and victor (2010) reported that spread ratio increased with the increasing level of substitution with quality protein maize. The inclusion of quality protein maize flour enhanced the spreadability of the biscuit samples which reduced with the level of replacement with quality protein maize.
CIE’ Color parameters
Colour is one of the most important quality factors of bakery products and appetite is stimulated by colour perceived by the consumer. The colour values as measured in Hunter Lab Color Quest XE colorimeter for developed biscuit are presented in Table 4. The colour scores of developed gluten free biscuits for all the treatment showed almost similar. Developed biscuit
i.
e. control sample scores colour value as 63.25 L* measurement indicates light colour of the biscuit, 7.70 a* measurement indicates towards redness and 20.44b* measurement towards yellowness, 21.88 Hue and 11.32 chroma. Treatment T
2 scores lightness value was 62.73, redness value 7.84, yellowness value was 20.47 with Hue 21.92 and chroma 11.12. The lightness value of treatment T
3 was 63.44, redness value was 7.63, yellowness value was 20.45 alongwith hue 21.82 and chroma 11.42. The lightness value of T
4 was 63.47, redness value was 7.63, yellowness value was 20.53 with hue 21.9 and chroma 11.43. Treatment T
5 scores lightness value was 63.45, redness value was 7.64, yellowness value was 20.46 with hue 21.83 and chroma 11.41. No vast difference was observed between control and other treatments.
Divyashree et al., (2016) reported that L* indicates the whiteness of the biscuits decreased from 68.41 in the control biscuits to 51.24 with the addition of 30 per cent buckwheat flour and 20 per cent chia seed flour.
Texture profile analysis
Biscuit hardness values are presented in Fig 1. Hardness values were recorded as the peak force applied to break the biscuits. Data showed that sample T
1, T
2, T
3, T
4 and T
5 had hardness values of 2994.3 g, 3598.3 g, 3750 g, 3773 g and 3838 g respectively. The formulation containing buckwheat flour, soyaflour and two varieties of rice flours resulted biscuits with significantly (p<0.05) harder texture than control biscuit which contains only rice flours. This increase is due to effect of buckwheat flour and soyaflour.
Lee and Beuchat (1991) reported that more strength was needed to break cookies incorporated with legumes flour. This might have resulted from incorporation of protein rich flour which tends to be a biscuit of harder texture. In the present study, incorporation of soyabean flour might contribute towards hardness. According to
Collar et al., (2007), addition of fibers affected the mechanical properties like increased hardness of dough. Presence of fibre in buckwheat may be responsible.