Investigation on the physicochemical properties of fortified yogurt containing pumpkin powder

Document Type : Research Paper

Authors

1 Graduated MSc Student, Department of Food Science and Engineering, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran

2 Food Science and Technology Research Center of East Golestan, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran

3 Assistant Professor, Faculty of Agriculture and Natural Resources, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran.

Abstract

Introduction: Today, consumers increasingly believe in the effects of food on their health, and food should provide the necessary nutrients to prevent nutrition-related diseases as well as improve their physical and mental condition. Therefore, functional foods have been considered with the aim of improving the nutritional status, most of which is related to low calorie foods. Like many popular dairy products, yogurt consumption shows significant growth; The popularity of this product is primarily due to its high content of calcium, vitamins, minerals and low levels of fat, and secondly due to its health-promoting effect and inhibition of harmful bacteria. In the fresh mass of the pumpkin (Cucurbita moschata), total carotenoid content, a major contributory factor in the high nutritional value of pumpkins, ranges from 2 to 10 mg/100 g, the content of vitamins C and E accounting for 9–10 mg/100 g and 1.03–1.06 mg/100 g, respectively (Hosseini Ghaboos et al., 2016; Nawirska et al., 2009). Pumpkin fruit is also a valuable source of other vitamins, e.g., vitamin A, B6, K, thiamine, and riboflavin, as well as minerals, e.g., potassium, phosphorus, magnesium, iron and selenium (Mirhosseini et al., 2015; Obradović et al., 2015). Since pumpkin is a valuable micronutrients source, dried pumpkin could be processed into powder for foods to increase fibers, vitamin A and mineral contents. In addition, pumpkin powder can be used in bakery products because of its highly-desirable flavor, sweetness and deep yellow-orange color (Salehi, 2020).
Material and methods: At first, the pumpkin and spinach were dried and powdered in controlled conditions. Fresh pumpkins (Cucurbita moschata) were purchased from local market. The pumpkin slices with 5 mm thickness were dried in an oven (45°C). The dried pumpkins were milled, powdered and passed through a 125 mesh screen (Hosseini Ghaboos et al., 2016). To prepare yogurts containing pumpkin, skimmed milk was used form yogurt production factory with 1.5% fat. In fact, milk that was homogenized with a homogenizer (at a temperature of 70-60 ° C and a pressure of 150-160 bar) and by a pasteurizer (temperature at 92 ° C for 5 minutes) was pasteurized in the required amount in 5 liter containers. The starter culture (2% at 42°C) and squash powders (0, 2.5, 5 and 7.5%) were added to the milk. Then they were filled and closed. Approximately 100 samples were prepared at each time. Then, incubation was performed until the sample acidity reached 65°Dornic. For this purpose, the acidity of the sample was measured every 5 minutes at the end of the predicted fermentation time (experimentally). The used cold-room was an industrial cell greenhouse. The samples were placed in such a way that all the samples were on the same level and position in the greenhouse, which is very important for the uniform heating of the samples. After incubation, the samples were refrigerated at 4°C. Viscosity was measured using a viscometer with an LV64 spindle at a constant shear rate of 40 rpm and a temperature of 8°C. For this purpose, 250 ml of the sample was poured into a 250 ml glass beaker and stirred with a plastic spoon for 20 seconds. After turning on the device, and 30 seconds, the viscosity in centipoises was reported. Acidity was measured every 30 minutes to measure the fermentation time since the samples were incubated. When the acidity reached 70 degrees Dornic, the acidity was measured once until the acidity reached 80 degrees of Dornic. For yogurt, 10 g of the sample was titrated in the presence of phenolphthalein using 0.1 normal NaOH and the result was expressed based on °Dornic degree.
Results and discussion: In this study, pumpkin powder in the amount of 0, 2.5, 5 and 7.5% in the formulation of 1.5% fat yoghurt was used and its chemical and rheological properties were studied for 20 days of storage. The results showed that the highest rate of syneresis (41.68%) was related to the interactions of the control sample with a shelf life of 20 days. The highest viscosity (3194 cp) was related to 7.5% pumpkin powder sample. The highest pH (4.39) was related to pumpkin powder 5%. The results also showed that the highest amount of acidity (74 °Dornic) was related to the control sample. The highest amount of total phenol (10 mg/g) and antioxidant activity (75%) was related to pumpkin powder 7.5%. The results showed that by adding 2.5% pumpkin powder to the yoghurt, the gel strength of sample was decreased and with increasing concentration up to 7.5%, its gel strength was increased but it is still less than the control sample. The results of comparing the means, the interaction effects of shelf life and pumpkin powder show that the highest rate of syneresis (41.68%) was related to the interaction effects of the control sample with a shelf life of 20 days. The results also showed that the lowest amount (39.98%) was related to the interaction effects of 5% pumpkin powder at a shelf life of 1 day, which was statistically 7.5% with a pumpkin powder at a shelf life of 1 day and pumpkin powder 5 and 5. 7.7% had no significant difference in shelf life of 12 and 20 days. According to the results of comparing the means, the highest viscosity (3173 cp) was related to the shelf life of 20 days and the lowest (3170 cp) was related to the first day of shelf life, which is statistically different from days 7 and 12. Based on the results of analysis of variance, the data showed that the effect of different levels of pumpkin powder and shelf life in terms of total phenol in yogurt showed a significant difference (P<0.05). As the results of comparing the means shows the highest amount of total phenol (10 mg/g) was related to pumpkin powder 7.5% and the lowest amount (8 mg/g) was related to pumpkin powder was at 0%.
Conclusion: In general, adding pumpkin powder to yogurt formulation can reduce the syneresis of the product and also increase its nutritional value.

Keywords


اکبر ر، سلطانی م و مصلحی شاد م، 1398. تاثیر استفاده از شیره‌ خرما بر ویژگی‌های کیفی ماست بدون چربی، پژوهش های صنایع غذایی، 29(4)، 215-201.
امیری عقدایی س س، اعلمی م و رضایی ر، 1389. بررسی تأثیر هیدروکلوئید دانه اسفرزه بر ویژگی ‌‌های فیزیکوشیمیایی و حسی ماست کم چرب، پژوهش های علوم و صنایع غذایی ایران، 6(3)، 209-201.
حسینی م، لشکری ف و قنبرزاده ب، 1399. تاثیر ترکیب هیدروکلوئیدهای اینولین- ژلاتین و پلی‌دکستروز - ژلاتین بر خصوصیات رئولوژیکی و حسی ماست کم‌چرب پری بیوتیک، پژوهش های صنایع غذایی،30(4)، 135-123.
رزمخواه شربیانی س، رضوی س م ع، بهزاد خ و مظاهری طهرانی م، 1389. بررسی تاثیر استفاده از پکتین، صمغ دانه‌های مرو و ریحان بر خصوصیات فیزیکوشیمیایی و حسی ماست چکیده بدون چربی، پژوهش های علوم و صنایع غذایی ایران، 6(1)، 45-33.
غیاثی ح، مقصودلو ی، خمیری م، صادقی ماهونک ع، 1391، فرمولاسیون ماست طعم دار میوه ای قالبی با استفاده از رنگ دانه طبیعی و بررسی ویژگی های آن، نوآوری در علوم و فناوری غذایی، 4(2)، 9-1.
نجف‌غفاری ط و حسینی‌قابوس س ح، 1398. اثر تغییر مقدار چربی بر ویژگی‌های شیمیایی و رئولوژیکی ماست حاوی پودر سیب زمینی ترشی در طی زمان نگهداری، پژوهش های صنایع غذایی، 29(4)، 169-153.
Baba SA and Malik SA, 2015. Determination of total phenolic and flavonoid content, antimicrobial and antioxidant activity of a root extract of Arisaema jacquemontii Blume. Journal of Taibah University for Science 9(4): 449-454.
Bakirci S, Dagdemir E, Boran, OS and Hayaloglu AA, 2017. The effect of pumpkin fibre on quality and storage stability of reduced‐fat set‐type yogurt. International Journal of Food Science and Technology 52: 180-187.
Behrad S, Yusof MY, Goh KL and Baba AS, 2009. Manipulation of probiotics fermentation of yogurt by cinnamon and licorice: effects on yogurt formation and inhibition of Helicobacter pylori growth in vitro. World Academy of Science, Engineering and Technology 60: 590-594.
Fadavi A, Pajohi‐Alamoti M, Karami M. 2020. Synergistic effect of peppermint and garlic essential oil on fate of Kluyveromyces marxianus in Zucchini Bouranee. Journal of Food Safety 40: 12779.
Guiné RPF and Barroca MJ, 2010. Effect of drying on the textural attributes of bell pepper and pumpkin. 17th International Drying Symposium (IDS) Magdeburg, Germany, 3-6 October.
Hosseini Ghaboos S H, 2016. Production of pumpkin powder with vacuum-infrared system and its use in the formulation of spong cake. In:  Food science and technology, Islamic Azad University, Science and Research Brach, Tehran, pp. 122.
Lotfizade Dehkordi S, Shakerian A and Mohammadi Nafchi A, 2013. Effect of extract from Tragopogon graminifolius DC. On properties sensory, shelf life and the viscosity rate yogurt. Journal of Herbal Drugs (An International Journal on Medicinal Herbs) 4(1): 49-57.
Mirhosseini H, Rashid NFA, Amid BT, Cheong KW, Kazemi M, Zulkurnain M, 2015. Effect of partial replacement of corn flour with durian seed flour and pumpkin flour on cooking yield, texture properties, and sensory attributes of gluten free pasta, LWT-Food Science and Technology 63: 184-190.
Nawirska A, Figiel A, Kucharska A Z, Sokół-Łętowska A, Biesiada A, 2009. Drying kinetics and quality parameters of pumpkin slices dehydrated using different methods. Journal of Food Engineering 94: 14-20.
Obradović V, Babić J, Šubarić D, Jozinović A, Ačkar Đ, Klarić I, 2015. Influence of dried Hokkaido pumpkin and ascorbic acid addition on chemical properties and colour of corn extrudates, Food Chemistry 183: 136-143.
Ravi U, Menon l and Anupama M, 2010. Formulation and quality assessment of instant dhokla mix with incorporation of pumpkin flour. Journal of Scientific & Industrial Research 69: 956- 960.
Salehi F and Aghajanzadeh S, 2020. Effect of dried fruits and vegetables powder on cakes quality: A review. Trends in Food Science & Technology 95: 162-172.
Salehi F, 2017. Rheological and physical properties and quality of the new formulation of apple cake with wild sage seed gum (Salvia macrosiphon). Journal of Food Measurement and Characterization 11(4): 2006-2012.
Salehi F, 2020. Recent applications of powdered fruits and vegetables as novel ingredients in biscuits: A review. Nutrire 45 (1): 1-10.
Shakerian A, Sohrabi M J and Ghasemi Pirbalouti A, 2012. Effect of Bakhtiari celery (Kelussia odoratissma Mozaff) on sensory properties and shelf life of set yogurt. Journal of Herbal Drugs (An International Journal on Medicinal Herbs) 3(1): 41-48.
Tamime A Y, Barrantes E and Sword AM, 1996. The effects of starch based fat substitutes on the microstructure of set-style yogurt made from reconstituted skimmed milk powder. Journal of the Society 8: 16-23.
White CH, Kilara A and Hui YH, 2008. Manufacturing yogurt and fermented milks. John Wiley & Sons.