such as deep frying (Dowd et al. 2010). This results in production of off-flavors and
reduces the shelf life of the oil. Therefore, sometimes, partial hydrogenation is
advised to avoid this situation, which also often leads to production of trans-fatty
acids (Sacks and Katan 2002).
In terms of fatty acids, oleic and linoleic are the dominant unsaturated fatty acids
contributing 18–24% and 42–52% of the total share of unsaturated fatty acids,
respectively, while palmitic and stearic acids are the major saturated fatty acids
(26–35%) present in cottonseed oil. It is cholesterol-free and quite high in tocopherols content, ascertaining both its nutritional content and natural antioxidant properties. During frying, these antioxidants are transferred to the food fried, imparting
them a comparatively longer shelf life and preserving their freshness. Average
tocopherol content of cottonseed oil is 65 mg/100 g of oil, which is further equivalent to 38 mg of α-tocopherol. Cottonseed oil has wide applications in deep frying,
baking, margarine, icing, whipped toppings, and salad dressings. Additionally, the
refined cottonseed oil also has some non-food applications such as biodiesel source,
in paint industry, and as environment friendly lubricant additive to base oils (Durak
and Karaosmanoglu 2004), which will be discussed in brief in the last section of this
chapter.
3.3.2 Protein
Cottonseed proteins are considered as potential source of nutrition for both animals
and plants. Along with topmost fiber crop worldwide, cottonseed is also regarded as
the best source for plant proteins after soybean (Ory and Flick 1994). After oil
extraction from cottonseed, whatever dry matter remains behind is known as CSM.
High concentration of toxic component known as gossypol restricts its use for
human consumption. However, the animals are capable of tolerating its presence.
Therefore, CSM (by-product of oil industry) is mainly used as an animal feed.
However, despite of much compositional variability, CSM is a rich source of protein
with 30–50% protein of dry matter (He et al. 2015). As per the findings of Cheng and
Hardy (2002), crude protein, fat, and phosphorus content of CSM from four different
locations of Southern USA varied from 34.9% to 41.3%, 1.43% to 3.70%, and
9.95% to 1.10%, respectively. Similarly, lysine, methionine, threonine, and tryptophan content of CSM also varies from 1.68% to 1.90%, 0.57% to 0.63%, 1.17% to
1.30%, and 0.42% to 0.47%, respectively. Along with variation in composition,
protein digestibility is also an issue of major concern in CSM. The main limiting
amino acid in cottonseed protein is lysine. During the process of oil extraction,
gossypol binds with epsilon (ε)-amino group of the lysine amino acid, resulting in
non-availability of this essential amino acid (Nagalakshmi et al. 2007). Huang et al.
2007 reported 0.72 as the ideal digestibility coefficient for crude protein present
in CSM.
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M. K. Sihag et al.
reduces the shelf life of the oil. Therefore, sometimes, partial hydrogenation is
advised to avoid this situation, which also often leads to production of trans-fatty
acids (Sacks and Katan 2002).
In terms of fatty acids, oleic and linoleic are the dominant unsaturated fatty acids
contributing 18–24% and 42–52% of the total share of unsaturated fatty acids,
respectively, while palmitic and stearic acids are the major saturated fatty acids
(26–35%) present in cottonseed oil. It is cholesterol-free and quite high in tocopherols content, ascertaining both its nutritional content and natural antioxidant properties. During frying, these antioxidants are transferred to the food fried, imparting
them a comparatively longer shelf life and preserving their freshness. Average
tocopherol content of cottonseed oil is 65 mg/100 g of oil, which is further equivalent to 38 mg of α-tocopherol. Cottonseed oil has wide applications in deep frying,
baking, margarine, icing, whipped toppings, and salad dressings. Additionally, the
refined cottonseed oil also has some non-food applications such as biodiesel source,
in paint industry, and as environment friendly lubricant additive to base oils (Durak
and Karaosmanoglu 2004), which will be discussed in brief in the last section of this
chapter.
3.3.2 Protein
Cottonseed proteins are considered as potential source of nutrition for both animals
and plants. Along with topmost fiber crop worldwide, cottonseed is also regarded as
the best source for plant proteins after soybean (Ory and Flick 1994). After oil
extraction from cottonseed, whatever dry matter remains behind is known as CSM.
High concentration of toxic component known as gossypol restricts its use for
human consumption. However, the animals are capable of tolerating its presence.
Therefore, CSM (by-product of oil industry) is mainly used as an animal feed.
However, despite of much compositional variability, CSM is a rich source of protein
with 30–50% protein of dry matter (He et al. 2015). As per the findings of Cheng and
Hardy (2002), crude protein, fat, and phosphorus content of CSM from four different
locations of Southern USA varied from 34.9% to 41.3%, 1.43% to 3.70%, and
9.95% to 1.10%, respectively. Similarly, lysine, methionine, threonine, and tryptophan content of CSM also varies from 1.68% to 1.90%, 0.57% to 0.63%, 1.17% to
1.30%, and 0.42% to 0.47%, respectively. Along with variation in composition,
protein digestibility is also an issue of major concern in CSM. The main limiting
amino acid in cottonseed protein is lysine. During the process of oil extraction,
gossypol binds with epsilon (ε)-amino group of the lysine amino acid, resulting in
non-availability of this essential amino acid (Nagalakshmi et al. 2007). Huang et al.
2007 reported 0.72 as the ideal digestibility coefficient for crude protein present
in CSM.
76
M. K. Sihag et al.