Grocery stores are filled with a wide array of milk options, ranging from traditional whole milk to plant-based alternatives derived from oats, nuts, and soy. Powdered milk stands out due to its extended shelf life, offering a practical solution for those who don't consume milk frequently. This article delves into the nutritional profile of powdered milk, its potential role in weight management, and its overall impact on health, drawing upon scientific evidence and established guidelines.
What is Powdered Milk?
Powdered milk, also known as milk powder or dried milk, is a manufactured dairy product created by evaporating milk to a state of dryness. This process extends its shelf life significantly, eliminating the need for refrigeration due to its low moisture content. Additionally, drying reduces bulk, making transportation more economical. Powdered milk products encompass dry whole milk, nonfat (skimmed) dry milk, dry buttermilk, dry whey products, and dry dairy blends.
Production of Powdered Milk
The production of dry milk involves several key steps:
- Reception, Clarification, Cooling, and Storage: Selecting high-quality raw milk is crucial.
- Standardization: Adjusting the fat content to meet the desired specifications.
- Heat Treatment: Eliminating pathogens through pasteurization. Pasteurized milk has been heated to 161 degrees Fahrenheit for at least 15 seconds to kill harmful bacteria, then cooled.
- Evaporation: Concentrating the milk to approximately 50% solids.
- Homogenization: Preventing fat separation and ensuring a uniform consistency.
- Drying: Removing the remaining water through spray-drying or roller-drying. In modern times, powdered milk is usually made by spray drying nonfat skimmed milk, whole milk, buttermilk or whey. Pasteurized milk is first concentrated in an evaporator to approximately 50 percent milk solids. Alternatively, the milk can be dried by drum drying. Milk is applied as a thin film to the surface of a heated drum, and the dried milk solids are then scraped off. Spray drying is the more popular option (1).
- Packaging: Sealing the powdered milk in airtight containers to maintain freshness.
During manufacturing, some beneficial nutrients, such as vitamin A, vitamin D, and calcium, may be added to produce fortified powdered milk.
Storage Conditions for Optimal Freshness
To preserve the quality of powdered milk, proper storage is essential:
Read also: Guide to Keto-Friendly Milk Substitutes
- Store in airtight containers, removing excess air before sealing.
- Keep in a dry, dark, and cool environment.
- Use within 6 months of opening for maximum freshness.
The shelf life of whole milk powder is typically one year, while goat's milk powder can last from 6 months to a year, and organic whole milk powder may remain viable for up to two years.
Varieties of Powdered Milk
Powdered milk is available in various forms, categorized by fat content and processing methods:
- Non-fat Dry Milk/Skim Milk Powder: Contains less than 1.5% fat.
- Whole Milk Powder: Contains 26 to 40% fat.
- High-Heat, Medium-Heat, and Low-Heat Skim/Non-fat Milk Powders: Classified based on processing methods and solubility.
Dry milk can also be derived from different types of milk, such as cow's milk, goat's milk, or camel's milk, with cow's milk being the most prevalent.
Nutritional Composition of Powdered Milk
Powdered milk boasts a dense nutritional profile, offering a concentrated source of essential nutrients.
Macronutrients and Calories
Powdered milk is naturally high in nutrients and contains a low percentage of water. Powdered milk contains only 2.47% water. Keep in mind that adding one cup of water to a quarter cup of dry milk can substitute for cup of liquid milk.
Read also: Guilt-Free Keto Frosting
- Calories: A quarter cup of powdered milk provides 159 calories.
- Protein: A quarter cup of dry milk provides 8.42g of protein. Milk powders are a source of high-quality protein, with the amino acids readily digestible and completely bioavailable. Cow's milk powder is recognized as an excellent source of high-quality protein. Protein accounts for 38% of the total solids-not-fat content of milk. Milk powder also contains small amounts of various enzymes. Of the total milk protein, about 80% is casein and 20% is whey protein. Caseins include alpha-casein, beta-casein, kappa-casein and gamma-casein. The whey proteins (also called milk serum proteins) are the proteins that remain soluble when caseins are coagulated by either enzyme or acid. The building blocks of protein are amino acids. There are about 20 amino acids in all, and at least nine of them are dietary essentials. Milk powders contain all of these essential amino acids, plus others that are required by children, in significant quantities.
- Fats: A quarter-cup serving of powdered milk contains 8.54g of fats, predominantly saturated fat (5.34g). Milk fat contributes unique characteristics to the appearance, texture, flavor and satiability of dairy foods and foods containing dairy ingredients. It is also a source of energy, essential fatty acids, fat-soluble vitamins and several other health-promoting components. Milk fat is not only characterized by a number of different fatty acids, but also by their chain length. Emerging science findings indicate that milk fat contains several components such as conjugated linoleic acid (CLA), sphingomyelin, butyric acid and myristic acid, which may potentially protect against major chronic disease.
- Carbohydrates: A quarter-cup serving of powdered milk provides 12.3g of carbohydrates, entirely composed of lactose. Lactose, the principal carbohydrate in milk powder, accounts for about 54% of the total solids-not-fat content of milk. Minor quantities of oligosaccharides, glucose and galactose are also present in milk powder. Researchers speculate that galactose may have a unique role in the rapidly developing infant brain. Lactose is the first and only carbohydrate every newborn mammal consumes in significant amounts. Because digestion of lactose is much slower than of glucose and fructose, lactose is considered relatively safe for diabetics. Some individuals have difficulty metabolizing lactose because of reduced lactase levels, a condition called lactase nonpersistence.
Vitamins and Minerals
Milk powders are high in soluble vitamins and minerals, including calcium, phosphorus, and magnesium, and can be used to fortify a wide range of products - just 100g of skimmed milk powder contains 1,300mg of calcium. Milk contains many of the vitamins essential for human growth. The vitamin content of milk powders is similar to what would be found in the fluid milk from which it was derived. Vitamin A plays important roles in vision, cellular differentiation, growth, reproduction and immune-competence. Vitamin D, a fat-soluble vitamin which enhances the intestinal absorption of calcium and phosphorus, is essential for the maintenance of a healthy skeleton throughout life. Vitamin E (mainly tocopherol) is an antioxidant, protecting cell membranes and lipoproteins from oxidative damage by free radicals. This vitamin also helps maintain cell membrane integrity and stimulate the immune response. One of the minerals showing the greatest deficiency in the world population is calcium. Milk products such as milk powders are a rich source of calcium. Calcium plays a critical role in maintaining bone health and preventing osteoporosis. Calcium is also crucial for nerve conduction, muscle contraction, heartbeat, blood coagulation, the production of energy and maintenance of immune function.
- Vitamins: Powdered milk is a good source of vitamins B12, C, B5, and B1. Ample amounts of folate, vitamin B6, vitamin D, vitamin E, vitamin K, and vitamin B3 can also be found in dry milk.
- Minerals: Powdered milk is also a great source of minerals, especially calcium, phosphorus, and potassium. Dry milk is in the top 5% of foods as a source of calcium and in the top 6% of foods as a source of potassium. Powdered milk provides high levels of magnesium and zinc as well. Dry milk contains sufficient levels of selenium, copper, manganese, iron, and choline. Dry milk is high in sodium, containing 119mg per quarter-cup serving.
Glycemic Index and Acidity
- Glycemic Index: Whole milk powder has glycemic index values similar to standard liquid whole milk. The glycemic index of powdered milk has been calculated to fall from 23±4 to 68±6, depending on the amount of added carbohydrates.
- Acidity: The acidity of powdered milk is close to neutral, with the pH value falling from 6.6 to 6.8.
Powdered Milk and Weight Management
Powdered milk's role in weight loss and various dietary approaches is a subject of interest.
- Calories and Fat Content: Whole powdered milk is high in calories, fats, and carbohydrates, while non-fat dry milk is significantly lower in fats and calories.
- Dietary Suitability: Non-fat, skim, or low-fat powdered milk is more suitable for low-fat or low-calorie diets.
Despite the high-calorie content, non-fat dry milk has been researched to help reduce weight gain and associated fatty tissue inflammation in diet-induced obese rats.
Powdered Milk in Specific Diets
- Keto: Powdered milk is not advisable on a keto diet due to its carbohydrate content.
- DASH: Powdered milk, especially whole-fat, should be avoided on a DASH diet due to its fat and sodium content.
- Atkins: Powdered milk is prohibited in Phase 1 but can be used in moderation from Phase 2 onwards.
- Mediterranean: Powdered milk is not typically included in a traditional Mediterranean diet.
- Paleo: Whether to include powdered milk in a paleo diet is a personal choice, as it was not consumed during the Paleolithic era.
- Vegan/Vegetarian/Pescetarian: Powdered milk fits into vegetarian and pescetarian diets but not vegan diets.
- Gluten-free: Powdered milk is a gluten-free product.
- Dukan: Non-fat milk powder can be consumed in moderation during the Attack phase, but it is not recommended.
- Intermittent Fasting: Dry milk should be avoided during fasting periods.
- Low Fat & Low Calorie: Non-fat or low-fat powdered milk can fit in a low-fat diet, while whole-fat dry milk does not. However, non-fat and whole-fat dry milk are high-calorie foods and do not fit in a low-calorie diet.
- Low Carb: Powdered milk is not suitable for a low-carb diet due to its carbohydrate content.
- Anti-Inflammatory: Research suggests that pasteurized and powdered milk display an anti-inflammatory effect.
- BRAT: Milk and dairy, including powdered milk, should be avoided on a BRAT diet, as consumption may worsen diarrhea.
Health Implications of Powdered Milk
Powdered milk shares similar health impacts with liquid milk, both positive and negative.
Health Benefits
- Cardiovascular Health: Fortified milk powder may reduce the risk of cardiovascular disease by reducing blood pressure and low-density lipoprotein levels.
- Diabetes: Milk powder, supplemented with insulin and resistant dextrin, has been researched to help improve glycemic control, insulin resistance, and blood pressure in elderly patients with type 2 diabetes mellitus.
- Bone Health: High-calcium milk powder effectively reduces bone loss in postmenopausal women and enhances bone growth in children.
- Cancer: Research has found an inverse association between milk consumption and the risk of colorectal and bladder cancer.
Downsides and Risks
- Lactose Intolerance: Individuals with lactose intolerance may experience digestive issues due to the lactose content in powdered milk.
- Milk Allergy: People with milk allergies should avoid powdered milk.
- Potential Cancer Risk: Some research suggests that the fat and hormones in dairy products may increase the risk for some cancers of the reproductive system, especially prostate, ovarian, and breast cancer.
Historical Perspective
While Marco Polo documented Mongolian Tatar troops carrying sun-dried skimmed milk in the time of Kublai Khan, the first modern production process for dried milk was invented by the Russian doctor Osip Krichevsky in 1802. The first commercial production of dried milk was organized by the Russian chemist M. Dirchoff in 1832.
Read also: Powdered Keto Sweeteners
Versatile Applications of Powdered Milk
Powdered milk finds applications in various settings:
- Food Aid: A common item in UN food aid supplies.
- Emergency Preparedness: Used in fallout shelters and warehouses.
- Infant Formula: Frequently used in the manufacture of infant formula.
- Survival and Hiking: Favored by survivalists and hikers for its nonperishable nature and ease of preparation.
- Developing Countries: Widely used due to reduced transport and storage costs.
- Confectionery and Baking: Used in chocolate, caramel candy, and baked goods.
- Sweets: Used in Indian milk balls (gulab jamun) and chum chum.
- Laboratory Applications: Fat-free powdered milk is used as a saturating agent in laboratory settings.
Appearance and Taste
Once reconstituted, powdered milk has a different flavor than other cow's milk beverages.