Comparative assessment of the physicochemical and biochemical properties of native and hybrid varieties of pumpkin seed and seed oil (Cucurbita maxima Linn.)

Abstract

The hybrid variety of Cucurbita maxima is commercially available and frequently used as food in Bangladesh compared to the native variety. Although the seeds of Cucurbita maxima have nutritional and therapeutic values, people in Bangladesh typically throw them away as waste. If we can explore their physicochemical and biochemical properties, this will add new knowledge to nutrition and food science. Thus, in this study, we compare the physicochemical and biochemical properties of native and hybrid varieties of pumpkin seed and seed oil. Solvent extraction methods were used to obtain oil. The physicochemical properties of the extracted seed oils were examined by titration methods and proximate compositions of pumpkin seeds were determined using the standard method. Tocopherols were analyzed by HPLC and fatty acids were identified by GC/MS as N-acylpyrolidines. The specific gravity, refractive index, viscosity, acid value, saponification value, iodine value and ester values were determined and among them iodine values and acid values were significant (p < 0.05) at native but saponification and ester values were very highly significantly (p < 0.001) at hybrid. The comparative lipid content in the seed of native variety was higher than hybrid (p < 0.01) and protein contents were higher but not significant. However, crude fiber content was higher in the hybrid (p < 0.01). There was no significant differences of moisture, ash, sugar and starch contents in between the two varieties. The total tocopherol, contents were very high (p < 0.001) in native. In hybrid, saturated fatty acids -capric acid, myristic acids were more (p < 0.001) but in native unsaturated fatty acid linoleic and linolenic acids were predominant (p < 0.05). Owing to the considerable differences in the physicochemical composition, the fatty acids and other properties, this study may suggest that the both varieties of pumpkin seed oil may be an alternative good source of edible oil.

Quality attributes of roasted Arabica coffee oil extracted by pressing: composition, antioxidant activity, sun protection factor and other physical and chemical parameters

“…Thirty-five volatile compounds of different classes (carboxylic acids, ketones, furans, thiols, pyrazines, phenols, pyridines, aldehydes, terpenes, alcohols, sulfur compounds, and thiazoles) were quantified in the oil (Table 5), several of them being described as typical of roasted coffee aroma (Akiyama et al, 2007;López-Galilea et al, 2006).…”

“…Ketones are also abundant in roasted coffee (Toledo et al, 2016), presenting aromas such as fruit, butter, mushroom, mold, caramel, and tea (López-Galilea et al, 2006;Akiyama et al, 2007). Maltol, present in higher contents (835.94 ng•g -1 ) ( Table 5), presents a caramel odor (Belitz et al, 2009).…”

“…Furans are described as the main chemical class found in Arabica coffee, followed by pyrazines, pyridines, and pyrroles (Toledo et al, 2016). They can give an aroma of roasted malt, sweet, grass, fruits, burnt, burnt sugar, and others (López-Galilea et al, 2006;Akiyama et al, 2007, Nascimento et al, 2007Belitz et al, 2009). The furan found in higher contents in the roasted coffee oil was furfuryl acetate (539.88 ng•g -1 ) (Table 5), which has a floral and fruity odor (Nascimento et al, 2007).…”

“…A high content in 2-furfurylthiol in the oil (727.16 ng•g -1 ) ( Table 5) was observed, which is a key aromatic compound in roasted coffee products (Toledo et al, 2016, Nascimento et al, 2007Belitz et al, 2009). Pyrazines are described as presenting aromas of nut, earth, roasted and grass (Czerny and Grosch, 2000;Akiyama et al, 2007;Toledo et al, 2016).…”

“…Quantification was performed by external standardization using duplicate 6-point analytical curves. Sensory attributes related to each volatile compound, based on those described in literature (Akiyama et al, 2007, Belitz et al, 2009. Dulsat-Serra et al, 2016, Toledo et al, 2016, and Kalschne et al, 2018, were also reported ( Table 5).…”