Physicochemical and Sensory Attributes of Pumpkin Seed Oil (Dodo Ikire Case Study)
Aim and Objective of the Study
The aim of the study is to determine the physicochemical and antioxidants activities of pumpkin seed oil (a case study of dodo ikire)
Specific Objective of the Study
The specific objective of this study includes the following
- To produce oil from pumpkin seed
- To prepare dodo ikire from ripe plantain
- To determine the physicochemical and sensory properties of pumpkin seed oil and dodo ikire
Pumpkin Seed (Cucurbita maxima)
Pumpkins (Cucurbit sp.) belonging to the Cucurbitaceae family are grown widely around the world as a vegetable. In the USA, they are vastly used for Halloween carvings and thanksgiving feasts. Most of the crops are processed into canned pumpkins or pie mix. However, the plentiful flat, oval seeds are generally discarded as agricultural residues. The seeds are uniquely flavoured with nutty taste and are consumed as roasted, salted snack in some parts of Canada, Mexico, USA, Europe and China. Now, grocery stores are also selling these seeds as baked, sprouted, fermented, pumpkin protein concentrate and pumpkin protein isolate, as their richness in protein, iron, zinc, manganese, magnesium, phosphorous, copper, potassium, polyunsaturated fatty acids, carotenoids and c-tocopherol is beginning to surface.
There is a growing interest in vegetable oils of special composition, and pumpkin seed oil is a promising candidate in this regard. Cold press or steam distillation is used for oil extraction. The dark greenish-red oil is used for cooking, as marinade or salad dressing and it has already been touted as a contender to olive oil. It is being used in many epicurean delights, viz. chocolate, cereal bar, bread, cake, muffin, soup, pesto, stew and pasta garnish. Pumpkin seed butter is considered as a great alternative to peanut butter. Major US food stores such as Costco, Trader Joes and Walmart sell myriad varieties of pumpkin seed-based food products, viz. granola chunks, tortilla chips, vegetable salad, sourdough bread, cookies and quinoa salad.
Pumpkin seeds and derived oil comprise a multi-million dollar industry in Europe. Most of the oil is manufactured in Austria, Slovenia, Serbia and Hungary. Its popularity is at the nascent phase in other regions of the globe, which slowly but surely is gathering momentum.
Pumpkin- General aspects
Classification of pumpkin includes;
Botanical Name: Cucurbita Maxima
Colour: Light yellow-orange to bright orange
Best season: Throughout the year
Pumpkin (English), kumbra (Bengali), kohul (Gujarati ), kaddu (Hindi), kumbala (kannada), paarimal (kashmiri ) mathan or chakkara kumbalanga (Malayalam ), Lal Bhopal (Marathi),kakharu (oriya ), sitaphal (Punjabi), purangikkai or pooshanik (tamil ), gummadi kayi (telugu) dungaree ( Sanskrit) (Gopalan et al., 2011).
Pumpkin belongs to the family Cucurbitaceae which is an angiosperm, genus Cucurbita with different varieties (Alfawaz, 2004). Normally pumpkin seeds are thrown away as a waste, whereas it is a rich source of nutrients and oil and can be used as a food (Dhiman, 2009). After the elimination of pulp, pumpkin seeds and rinds which remain in large quantities as waste product could be consumed for edible purpose (Abd EI-Aziz and EI-Kalek, 2011). The antimicrobial activity of pumpkin has many applications, including preservation, pharmaceuticals, alternative medicine and natural therapies (Rajakaruna et al., 2002).
Pumpkin seeds indeed are an excellent source of dietary fiber and monounsaturated fatty acids, which are good for heart health. In addition, the seeds are concentrated sources of protein, minerals and health-benefiting vitamins. For instance, 100 g of pumpkin seeds provide 559 calories, 30 g of protein, 110% RDA of iron, 4987 mg of niacin (31% RDA), selenium (17% of RDA), zinc (71%) etc., but no cholesterol. Further, the seeds are an excellent source of health promoting amino acid tryptophan. Tryptophan is converted to GABA in the brain.
Constituents of pumpkin seeds
Nuts are nutrient dense foods. They contain high amounts ofprotein and fat, mostly unsaturated fatty acids. Nuts are alsodense in a variety of other nutrients and provide dietaryfibre, vitamins (e.g. folic acid, niacin, vitamin E, vitamin B6), minerals (e.g. copper, magnesium, potassium, zinc) and many bio-active constituents such as antioxidants, phytosterols and other phytochemicals (Dreher and Maher, 2006). Pumpkin seeds contained relatively large amounts of magnesium Mg (5690); zinc Zn (113); copper Cu (15.4); molybdenum Mo (0.805) and another minerals: phosphorus P (15700); calcium Ca (346); iron Fe (106); manganese Mn (49.3); aluminum Al (9.21); barium (1.16); cobalt Co (0.29); strontium Sr (1.83); nickel Ni (0.53); arsenic (0.45) (in μg/g dry weight). Noteworthy are the low amounts of calcium in the seeds (Glew et al., 2006).
Pumpkin seeds are an excellent natural source of essential vitamins and minerals healthy oils and fiber. Boiled, baked or even raw, pumpkin seeds are packed full of vitamins, minerals and amino acid. Just one serving (about 1/4cup) pumpkin seed gives you almost half recommended daily amounts of manganese ,magnesium ,phosphorus , iron, copper, vitamin K and zinc. Pumpkin seeds are a good source of protein and Monounsaturated fats
Chemical composition of pumpkin seed
Pumpkin active ingredients include essential fatty acids, amino acids, phytosterols (including beta- sitosterol), minerals and vitamins. Seed kernels of pumpkinare rich in fat soluble vitamins, oil and protein, containing considerable amounts of P, K, Mg, Mn, and Ca. Roasted pumpkin contains a significantly high amount of carotenoids; especially zeaxanthin. Pumpkin seed kernel flour has high values of chemical score, essential amino acid index, and in vitro protein digestibility. Pumpkin Seed Oil has high amounts of unsaturated fatty acids with linoleic and oleic acids as the major acids. Pumpkin possess an unusual amino acid known as cucurbit in has been chemically defined as (-)-3-amino3-carboxy pyrimidine (The Columbia Encyclopedia. 2004).
The pumpkin seeds contained 39.25% crude protein, 27.83% crude oil, 4.59% ash, and16.84% crude fiber; the corresponding values for the kernels were 39.22, 43.69, 5.14, and 2.13%, respectively. Pumpkin seed kernels contained moderate concentrations of minerals, especially P, Mg, and K. The amino acid profiles indicate that methionine and tryptophan were the most limiting amino acids, while arginine, glutamic, and aspartic acids were the most plentiful amino acids. The saturated fatty acid content was 27.73% and comprises of 16.41% palmitic acid and 11.14% stearic acid. The unsaturated fatty acid value was 73.03% and consisting mainly of 18.14% oleic acid and 52.69% linoleic acid. The oil obtained from the pumpkin seed kernels had a refractive index of 1.4656, specific gravity of 0.913, iodine value of 105.12 (g I2/100g oil) saponification value of 185.20 (mg KOH/g oil), acid value of 0.53 (mg KOH/g oil), and peroxide value of 0.85 (meq peroxide/kg oil). Considering the lipid and protein content in the kernels, and their fatty and amino acid compositions, the pumpkin seed kernels appear to be quite promising for commercial exploitation (Mohammed, 2004).
MATERIALS AND METHODS
Collection of Materials
Pumpkin seed were obtained from Emure-ile market in Owo, Ondo State. The pumpkin seed was processed in the processing laboratory of Food Science and Technology, the analysis was carried in the Chemistry Laboratory of Food Science and Technology, Rufus Giwa Polytechnic, Owo, Ondo State.
Sample Preparation (Methods)
Preparation of pumpkin seed
The seeds were removed from the fruits, washed and sun dried for two weeks until they were properly dried at daily temperature of 33oC.The outer layer of the seeds were removed and then subjected to mechanical grinding. Powdered seeds were obtained and dried at 37oC and preserved in clean sealed polyethylene bags.
RESULTS AND DISCUSSION
Table 4.1: Proximate composition of dodo ikire fried with pumpkin seed oil
CONCLUSION AND RECOMMENDATIONS
The study revealed that dodo ikire fried with pumpkin seed oil was observed to have the appreciable proximate composition, the moisture content was observed lowest in DPS. The fat and fibre content was also observed highest in DPS, DPO was revealed to have the maximum ash content while the protein and carbohydrate content was noted maximum for sample DCPO. The free fatty acid of DPS is in range of the standard value for vegetable oil which is 3.3%. Dodo ikire fried with pumpkin seed oil was generally accepted in terms color, taste, texture and appearance, this indicate that pumpkin seed oil improve the sensory attributes of dodo ikire. In conclusion, pumpkin seed oil has the highest nutritional qualities and the most acceptable sensory attributes of dodo ikire.
Based on the finding above it is therefore recommended that more research should be carried out on the antioxidant properties of the pumpkin seed oil this will contributes to the existing knowledge of the oil which help enhance its utilization in Nigeria.
- Abdelaziz, A.B. and Elkalek, A. (2011). Antimicrobial proteins and oil seeds from pumpkin (Cucurbita moschata). Nature and Science, 9:105 – 119.
- Abdulkadir, A.G. and Jimoh, W.L.O. (2013): Comparative Analysis of PhysicoChemical Properties of Extracted and Collected Palm Oil and Tallow. Chem Search Journal. 4(2): 44 –54, Dec. Publication of Chemical Society of Nigeria, Kano Chapter.
- Abdulkarim, A.M., Ameh, D.A., Ibrahim, S., Ayo, J. and Ambali, S.F. (2005b). Effect of fermented and unfermented seed extracts of Carica papaya on pre-implantation embryo development in female Wistar rats (Rattus norvegicus). Scientific Res. Essay. 4(10):1080-1084.
- Adewole, M.B. and Duruji, R.W. (2010): Quality assessment of plantain (musa paradisiaca l.) as affected by different ripening methods. African Journal of Biotechnology 9(38): 6290-6293.
- Alfawaz, M.A. (2004). Chemical composition and oil characteristics of Pumpkin (Cucurbita maxima) seed kernels. Res. Bult. No (129), Food Sci. Agric. Res. Center, King Saud Univ. 5 – 18.
- Andjelkovic, M., Van Camp, J., Trawka, A. and Verhe, R. (2010). Phenolic compounds and some parameters of pumpkin seed oil. Euorpian Journal of Lipid Science 112(2): 208-217.
- Andrikopoulos, N. (2004). Tricylglycerol species of less common edible vegetable oil. Food Rev Int,Vol. 20,Pp.389-405.