Research Article

Proximate Analysis, Phenolic Compounds and Antioxidant Activity of Milk Products Commonly Consumed in Khyber Pakhtunkhwa, Pakistan

Shakeel Ahmad1*, Humaira Wasila2, Juweria Abid3, Nazir Muhammad4 and Hazrat Usman5

1Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical University, Nanjing 211166, China; 2Department of Human Nutrition, The University of Agriculture, Peshawar, Khyber Pakhtunkwa, Pakistan; 3Department of Nutrition and Dietetics, National University of Medical Sciences Rawalpindi, Pakistan; 4Department of Environmental design, Health and Nutritional Sciences, Allama Iqbal Open University, Islamabad, Pakistan; 5Department of Food Science and Technology, The University of Agriculture, Peshawar, Pakistan.

Received | April 27, 2022; Accepted | June 28, 2022; Published | October 15, 2022

*Correspondence | Shakeel Ahmad, Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Email: [email protected]

Citation | Ahmad, S., H. Wasila, J. Abid, N. Muhammad and H. Usman. 2022. Proximate analysis, phenolic compounds and antioxidant activity of milk products commonly consumed in Khyber Pakhtunkhwa, Pakistan. Journal of Innovative Sciences, 8(2): 188-194.

DOI | https://dx.doi.org/10.17582/journal.jis/2022/8.2.188.194

Keywords | Milk products, Proximate composition, Phenolic compounds, Antioxidant activity

Copyright: 2022 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

1. Introduction

Milk is defined as the whole, clean and fresh lacteal secretion obtained by the complete milking of one or more animals (Hui and Yiu, 1993). In fresh form, milk has maximum nutritious value because it contains a high amount of proteins, fats, carbohydrates, vitamins and minerals in comparison with other food items (Neumann et al., 2002).

Pakistan is one of the major milk-producing countries. The main sources of milk include buffalo, cow, camel, sheep, and goat. Currently, Pakistan has 27.33, 29.56, 0.92, 26.49, and 53.79 million buffalo, cows, camels, sheep, and goats, respectively (GOP, 2006). Among the topmost milk-producing countries, Pakistan lies in 4th while America is first, Russia in 2nd and India lies in 3rd position. On an annual basis, Pakistan produces about 45 billion liters of milk (Iqbal et al., 2011).

Milk products are a rich source of minerals like zinc, phosphorus, calcium, potassium, magnesium and selenium, as well as vitamins, like vitamin A and vitamin B complex (Iqbal et al., 2011). Due to the presence of a significant amount of phenolic compounds, the importance of milk products is increased, which maximized their production (O’Connell and Fox, 2001). Many studies confirmed that milk products contain a variety of antioxidant molecules like carotenoids, retinol, thiols, tocopherol and ascorbate (Nozière et al., 2006).

Milk products are extensively eaten worldwide and have financial value. Milk products contribute about 10% of total energy and 15-25% of fat and protein requirements (Yildiz, 2009). Milk products are commonly consumed in the Khyber Pakhtunkhwa district of Pakistan and have high demand. Due to increased demand, this study was designed to find out the composition of macronutrients, minerals, phenolic compounds and antioxidant activity of milk products commonly consumed in Khyber Pakhtunkhwa Pakistan.

2. Materials and Methods

2.1 Study site

The study was conducted in the laboratory of Human Nutrition, The University of Agriculture Khyber Pakhtunkhwa, Pakistan.

2.2 Sample collection

Fifteen different milk products locally produced and consumed were selected for this study, including yogurt, cream, butter, buttermilk, cheese, khoa, black tea with milk, green tea with milk, milky ladu, burfi, sohan halwa, mardani paida, rasgulla, gulabjamun and manpasand.

Milk products were purchased from three different local markets in Khyber Pakhtunkhwa by simple random sampling technique. Composite samples were made for further laboratory work.

2.3 Sample drying and storage

Samples were dried in an oven at 65oC temperature for three days. A commercial grinder was used to grind milk products. Then samples were stored at room temperature in plastic jars.

2.4 Proximate composition of milk products

Association of official analytical chemists 15th edition procedures were followed for proximate analysis of milk products. It assumed the amount of carbohydrates, protein, fats, ash and moisture contents. All chemical analysis was conducted in triplicate (Association of Official Analytical Chemists and Helrich, 2000).

2.5 Minerals determination

To determine elements like calcium, phosphorus, iron and zinc, the method of (Polyakova and Shuvaeva, 2005) was used. Atomic absorption spectroscopy and flame photometry were used for mineral analysis.

2.6 Phenolic compounds and antioxidant activity

Total phenolic compounds were evaluated by the Folin-Ciocalteu method with slight modification (Singleton et al., 1998). The aluminum chloride colorimetric method of (Chang et al., 2002) was used for the evaluation of total flavonoid content. Antioxidant activity was assessed according to the procedure of (Molyneux, 2004).

2.7 Statistical analysis

Statistical software statistix 8.1 was used in which one-way repeated ANOVA was used for multi comparison, and all the results were represented by mean±SD.

3. Results and Discussion

Milk products are commonly consumed in the Khyber Pakhtunkhwa district of Pakistan and have high demand. Due to increased demand, this study was designed to determine the composition of macronutrients, minerals, phenolic compounds and antioxidant activity of milk products commonly consumed in Khyber Pakhtunkhwa.

The proximate composition of milk products commonly consumed in Khyber Pakhtunkhwa is given in Table 1. Moisture contents ranged from 92.15±0.13 g/100g seen in Buttermilk to 0.84±0.06 g/100g seen in Manpasand. The highest ash contents were observed in Manpasand (5.71±0.03g/100g), while the lowest was observed in Butter (0.11±0.42g/100g). Similarly, maximum carbohydrates were present in Mardani paida (79.69±0.14g/100g), and the lowest carbohydrates were present in Buttermilk (2.13±0.02 g/100g). Protein in the highest amount was examined in Manpasand (25.36±0.04g/100g), and protein in the lowest amount was examined in Sohan halwa (0.43±0.25 g/100g). In the same way, the topmost fats were noted in Butter (81.71±0.04g/100g), and the lowermost fats were noted in Yogurt (0.77±0.04g/100g).

Minerals contents of milk products commonly consumed in Khyber Pakhtunkhwa are presented in Table 2. Maximum calcium (612.00±0.01mg/100g) was observed in Khoa, and the least calcium (15.22±0.03 mg/100g) was observed in Butter. The highest amount of zinc was seen in Cheese (4.80±0.05a mg/100g), while the lowest zinc was seen in Butter (0.109±0.02 mg/100g). Similarly, the utmost quantity of iron was examined in Rasgulla (5.60±0.05 mg/100g), and the least quantity of iron was examined in Buttermilk (0.110±0.05mg/100g). Maximum phosphorus content was determined in Mardani paida (401.60±0.04 mg/100g) while, the lowest phosphorus content was determined in Butter (25±0.01 mg/100g).

Phenolic compounds of milk products commonly consumed in Khyber Pakhtunkhwa are shown in Table 3. The highest total phenolic compounds were seen in Green tea with milk (37.04±0.61 mg GAEb/100g), while the lowest total phenolic compounds were seen in Manpasand (12.07±0.86 mg GAEb/100g). In the same way, the topmost flavonoids were observed in Green tea with milk (12.02±0.06 mg QEc/100g) and the lowermost flavonoids were observed in Cream (3.45±0.04 mg QEc/100g). Due to the presence of phenolic compounds, the highest antioxidant activity was detected in Green tea with milk (18.44±0.05 mgVCEd/100g) and the lowest antioxidant activity was detected in Rasgulla (7.59±0.23 mgVCEd/100g).

The correlation between total phenolic compounds, total flavonoids and antioxidant activity is given in Table 4. A significant correlation was seen (0.676 (P < 0.01)) between total phenolic compounds and total flavonoids. In the same way, a strong significant correlation (0.805(P < 0.01)) was observed between total flavonoids and antioxidant activity. Similarly, a significant positive correlation was noted (0.667 (P < 0.01)) between total phenolic compounds and antioxidant activity.

 

Table 1: Proximate analysis of milk products commonly consumed in Khyber Pakhtunkhwa (g per 100g wet weight).

Milk products	Moisture	Ash	Carbohydrates	Protein	Fat
Butter milk	92.15±0.13a	0.38±0.021jk	2.13±0.02m	3.71±0.14h	1.53±0.01n
Black tea with milk	79.09±0.09d	4.80±0.04b	5.04±0.10k	5.06±0.05g	5.92±0.21k
Green tea with milk	80.21±0.18c	4.60±0.05c	4.70±0.12l	5.26±0.42f	5.10±0.30l
Yogurt	86.46±0.32b	0.42±0.01j	11.32±0.40i	1.02±0.02l	0.77±0.04o
Cream	54.47±0.09e	0.70±0.54i	4.78±0.24kl	2.41±0.01j	25.33±0.22c
Butter	15.80±0.01h	0.11±0.42l	2.19±0.12m	0.98±0.04l	81.71±0.04a
Cheese	54.47±0.06e	3.91±0.14d	5.73±0.21j	15.01±0.05d	20.86±0.05f
Khoa	17.41±0.01g	3.31±0.22e	31.77±0.10h	17.76±0.12c	35.73±0.13b
Milky ladu	14.29±0.26i	0.90±0.24h	66.33±0.20d	1.66±0.13k	16.63±0.15i
Burfi	7.23±0.03k	0.37±0.02jk	72.34±0.10b	1.90±0.43k	18.26±0.43h
Sohan halwa	11.43±0.01j	0.21±0.03kl	68.15±0.10c	0.43±0.25m	19.77±0.14g
Mardani paida	2.35±0.02m	1.30±0.01g	79.69±0.10a	3.06±0.17i	13.60±0.02j
Rasgulla	51.27±0.03f	2.01±0.11f	34.35±0.70g	8.24±0.07e	4.15±0.10m
Gulabjamun	6.22±0.02l	4.57±0.10c	48.27±0.10e	19.43±0.19b	21.51±0.03e
Manpasand	0.84±0.01n	5.71±0.03a	45.34±0.21f	25.36±0.04a	22.73±0.32d

 

Values expressed as Mean±SD. Values with same letter(s) in each column are not significantly different at P < 0.05.

 

Table 2: Mineral analysis of milk products commonly consumed in Khyber Pakhtunkhwa (mg/100g).

Milk products	Calcium	Zinc	Iron	Phosphorus
Butter milk	90.99±0.01l	0.388±0.02e	0.110±0.05n	68.72±0.03k
Black tea with milk	140.04±0.02k	0.117±0.03l	0.730±0.03d	102.28±0.05j
Green tea with milk	148.06±0.05j	0.123±0.02k	0.680±0.02e	107.5±0.01i
Yogurt	201±0.05i	0.750±0.05d	0.127±0.04m	173±0.04h
Cream	51±0.02n	0.228±0.021f	0.202±0.01l	51±0.03l
Butter	15.22±0.03o	0.109±0.02m	0.201±0.02l	25±0.01n
Cheese	520.02±0.02b	4.80±0.05a	1.55±0.02c	392±0.02b
Khoa	612.0±0.01a	3.605±0.04b	2.75±0.04b	364.0±0.03c
Milky ladu	392.8±0.04f	0.180±0.02g	0.391±0.01k	312.04±0.01f
Burfi	464±0.12d	0.175±0.01h	0.589±0.02f	392.20±0.02b
Sohan halwa	316.05±0.01h	0.116±0.011	0.512±0.03h	288.50±0.01g
Mardani paida	515.02±0.04c	0.133±0.05j	0.484±0.02i	401.60±0.03a
Rasgulla	63.04±0.01m	1.245±0.03c	5.60±0.05a	45.56±0.05m
Gulabjamun	410.04±0.01e	0.171±0.02h	0.411±0.03j	360.40±0.02d
Manpasand	390.5±0.05g	0.151±0.04i	0.569±0.05g	344.60±0.05e

 

Values are expressed as Mean±SD. Values with same letter(s) in each column are not significantly different at P < 0.05

 

Table 3: Phenolic compounds and antioxidant activity of milk products commonly consumed in Khyber Pakhtunkhwa.

Milk products	Total phenolic compounds (mgGAEb/100g)	Total flavonoids (mg QEc/100g)	Antioxidant activity (mgVCEd/100g)
Butter milk	29.93±0.83c	7.50±0.02d	13.78±0.93c
Black tea with milk	34.84±0.24b	11.20±0.07b	17.50±0.32b
Green tea with milk	37.04±0.61a	12.02±0.06a	18.44±0.05a
Yogurt	18.58±0.64i	9.05±0.32c	13.77±0.20c
Cream	20.82±0.61h	3.45±0.04o	7.78±0.87m
Butter	24.63±0.52e	4.61±0.05k	8.99±0.38l
Cheese	13.61±0.53m	5.99±0.02f	12.20±0.26f
Khoa	20.84±0.84h	7.04±0.05e	12.41±0.35e
Milky ladu	17.91±0.68j	4.12±0.04m	9.48±0.25k
Burfi	26.16±0.82d	4.92±0.02i	11.80±0.23g
Sohan halwa	16.50±0.34k	3.82±0.03n	9.95±0.46j
Mardani paida	21.80±0.38g	4.75±0.12j	11.40±0.11h
Rasgulla	15.34±0.45l	5.57±0.02g	7.59±0.23n
Gulabjamun	22.29±0.25f	4.52±0.07l	10.61±0.30i
Manpasand	12.07±0.86n	5.08±0.04h	12.56±0.45d

 

Values are expressed as Mean±SD. Values with same letter(s) in each column are not significantly different at P < 0.05.

 

Knowledge of the macromineral and trace element composition of milk products is important because of its wide use and nutritional importance. The macro density of milk products depends on factors like the genetics of lactating animals, environmental conditions, lactation stage, pasture type, manufacturing procedures and added ingredients in the processing of milk products (Sola-Larrañaga and Navarro-Blasco, 2009).

 

Table 4: Correlation between total phenolic compounds (TP), total flavonoids (TF) and antioxidant activity (AA).

	TF	AA	TP
TP	0.676 (P < 0.01)**
TF		0.805(P < 0.01)**
AA			0.667 (P < 0.01)**

 

**Correlation coefficients were significant at (P ≤ 0.01).

 

Moisture contents of the current study on yogurt were supported by (Olugbuyiro and Oseh, 2011). Ash contents in Buttermilk were closely related to the results of (Munde, 2015). Similarly, carbohydrates in Gulabjamun were confirmed by the findings of (Kumar, 2005). Correspondingly, protein in Cheese was matched with observations of (Sameen et al., 2008). Likewise, protein in Khoa was the same as determined by (Sameen et al., 2008). The findings of fats in Rasgulla were parallel to figures of (Puniya, 2015).

Milk products are rich in micronutrients like calcium, phosphorous, iron, and zinc (Ataro et al., 2008). National dairy council provided mineral contents such as phosphorus, calcium, magnesium, zinc, iron, manganese, selenium, copper, iodine, chloride, potassium and sodium levels in milk products (Dairy Products and Foods U.S. Dairy, n.d.). Fermented milk products contain more than 20 different elements. Elements like copper, zinc, manganese, and iron are essential, and they are very important for normal metabolism, growth, and development (Khan et al., 2014). On the other hand, elements such as lead, chromium, mercury, and cadmium are very important because of their toxicity and metabolic roles (Dervisoglu et al., 2014). The most vital mineral in milk products is calcium. National Academies of Science indicates the dietary reference intake for calcium that 800 mg per day for 3–8 years old, 1300 mg per day for 9–17 years old, and 1200 mg per day for people over 50 years. Vitamins and minerals are important for human life. They play vital roles in metabolic functions like maintenance of pH, nerve conductance, osmotic pressure, muscle contraction, bone health, energy production and in almost all aspects of body growth (Institute of Medicine US, 1997). Calcium in yogurt, butter and cream was endorsed by (Sameen et al., 2008). Similarly, zinc in rasgulla was proven by (Prodhan et al., 2017). Iron in cheese was supported by the results of (Singh et al., 2016). Phosphorus in cheese, yogurt, cream and butter was seen as the same as calculated by (Zamberlin et al., 2012). Zinc in Cheese was the same as observed by (Singh et al., 2016).

Dairy products are one of the most interesting and promising foods with regard to their potential antioxidant activity due to their wide diversity of antioxidant molecules such as milk caseins and whey proteins (Pihlanto, 2006). Furthermore, milk contains a variety of antioxidant molecule traces i.e. low molecular weight thiols (Niero et al., 2015), ascorbate, tocopherol, retinol and carotenoids (Niero et al., 2017). Total phenolic compounds in Yogurt was somehow related to results of (Ramos et al., 2017); minor changes might be due to the selection of raw material for Yogurt preparation. Total flavonoids in Yogurt were supported by the findings of (Qureshi et al., 2017). Total phenols in Black tea with milk were the same as proven by (Liebert et al., 1999). Antioxidant activity in green tea with milk was matched with the results of (Mahmood et al., 2014). Medicinal plants rich in natural antioxidants and phenolics are progressively applied in dairy food manufacturing to improve nutritional and therapeutic properties, which may help in the prevention and control of different diseases (Bertolino et al., 2015).

Conclusions and Recommendations

Nutritional information regarding milk products is available now and would serve as a basis for planning normal and therapeutic diets. It will help individuals to make a better choice by comparing milk products for their macronutrient contents and addressing major nutrition disorders that are related to the diet of the community. Milk products contain phenolic compounds which show antioxidant activity. Data on the nutritional composition of milk products can be used by health care workers and nutritionists to calculate energy and nutrients intakes.

Novelty Statement

This is the first ever study which observed the nutritional composition of milk products commonly consumed in Khyber Pakhtunkhwa, as well as phenolic compounds and antioxidant activity of these products, which makes it a novel study.

Author’s Contribution

All authors equally contributed to this research.

Conflict of interest

The authors have declared no conflict of interest.

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