Abstract:
Nowadays the trend to consume breakfast cereal bars and snack bars in
Thailand is increasing. Currently there are several brands of snack bars in the
market. The ingredients that boost the health appeal of snacks range from fruits to
vitamins. Phytonutrients are also becoming a popular addition to many emerging
products while taste, texture, and product stability need to be maintained.
Therefore, the application of soy protein ingredients into snack bars could present
an effective way to balance different quality parameters i.e. nutrition, health and
eating qualities. For this reason, incorporation of soy protein ingredients into
snack bars was investigated. Different types of soy protein ingredients namely
full-fat soy flour (FF), defatted soy flour (DF) and isolated soy protein (ISP) were
used as ingredients in the formulation. The objective of this study was to
formulate snack bar products with the addition of soy protein ingredients with
acceptable sensory qualities and determine their isoflavones content by High
performance liquid chromatography (HPLC).
Soy protein ingredients were added into snack bar a control formula starting
from 5% (w/w) increasing at 5% increment level. The products were slightly
lighter in color and significantly more brittle (p<0.05) when compared to the
control formula. The snack bar with 15% addition of FF and DF as well as 10%
addition of ISP could provide desirable organoleptic properties as denoted by
sensory evaluation. For total isoflavones analysis, among all 3 types of soy
protein ingredients, DF had the highest value of total isoflavones content (258.7
mg/100g, dry basis), and FF and ISP had 189.8 mg/100g and 144.7 mg/100g,
respectively. The major form of isoflavones was found to be glucosides with only
a small amount of aglycones. As expected, in soy protein ingredient-added snack
bars, total isoflavones content increased with increasing level of soy protein
ingredient. The 15% DF-added snack bar contained 42.0 mg/100g of total
isoflavones content when compared with 23.9 and 15.9 mg/100g in FF- and ISPadded
snack bar, respectively.
In addition, the protein content of soy protein ingredient-added snack bar was
approximately 2 times that of the control formula