Nutrition: Health Benefits of Yogurt. Food Science: How to Make Yogurt

 

Milk and eggs contain proteins that have the highest biological values nutritionists would tell you.

Milk for instance is the only food for human babies for at least 6 months and supplementary feeding needs to be given after that period for at least 2 years or longer. Milk can support the growth of not only human babies, but also calves, clubs, kits, pups, or whelps, of all mammalian carnivorous or omnivorous species of animals because nutritionally it is a complete food by itself. The main nutrient in milk that supports this growth is its very high-quality protein complete with all the amino acids.  

So is hen’s egg on which the entire unhatched chick depends inside its shell until it hatches 20 -21 days later or up to 30 days for other poultry. Eggs are also an excellent source of high-quality protein known as its biological value (BV) which is a measure of how efficiently the body utilizes protein from food. Eggs and milk BV are close to 100.

Foods with high biological values typically contain all the essential amino acids in proportions similar to those required by humans. They contain all the essential amino acids needed by the body.

Like eggs, milk is also a nutritionally good supplementary food even for adults. Besides milk and eggs here's a list of foods with high biological value

Whey Protein: Derived from milk, whey protein is considered one of the highest BV proteins available. It's quickly absorbed by the body and rich in essential amino acids.

1. Fish: Particularly oily fish like salmon, tuna, and mackerel are rich in protein and have high BV. They also provide omega-3 fatty acids, which are beneficial for heart health.
2. Lean Meats: Lean cuts of beef, pork, and poultry are rich in protein and have high BV. Choose lean cuts to minimize saturated fat content.
3. Dairy Products: Milk, yogurt, and cheese are good sources of protein with relatively high BV. They also provide calcium and other essential nutrients.
4. Soy Products: Soybeans and soy products like tofu and tempeh are plant-based sources of protein with high BV. They are also suitable alternatives for vegetarians and vegans.
5. Quinoa: Among grains, quinoa stands out for its high protein content and balanced amino acid profile, resulting in a relatively high BV for a plant-based food.
6. Cottage Cheese: Cottage cheese is a dairy product that's rich in protein and has a high BV. Milk is a popular choice for athletes and those looking to increase protein intake and to build up their strength and body mass.

These foods with high protein content and high BV provide the body with essential amino acids in proportions that closely match human requirements, making them highly effective for supporting muscle growth and preventing loss of body weight.

However, I also mentioned in a separate article milk may not be well tolerated by adult Asians.  Drinking milk in adults may cause diarrhoea due to the presence of milk sugar (lactose) inside. See my explanation here published on 

 Tuesday, June 20, 2023

Why Most People Cannot Tolerate Drinking Milk

https://scientificlogic.blogspot.com/search?q=lactose+intolerance+

We can solve this problem by converting the milk into yogurt by introducing milk bacteria such as Lactobacillus bulgaricus and Streptococcus thermophilus to ferment the lactose (milk sugar) into lactic acid. This process not only thickens the milk but also changes its flavour and nutritional composition slightly. Once the milk sugar lactose is converted into lactic acid and is no longer there, the yogurt is very well tolerated and should no longer cause diarrhoea.  If milk is converted into yogurt, will it retain its high protein biological values? We shall answer that later.

When milk is converted into yogurt, it undergoes a fermentation process where beneficial bacteria will be very useful for gut health. These bacteria called the probiotics found in yogurt are also found in the gut. There are several other types of probiotics that contribute to gut health. Some common ones include:

Lactobacillus: This is a type of bacteria commonly found in yogurt and other fermented foods. It helps in the breakdown of lactose and supports overall digestive health.

Bifidobacterium: Another group of bacteria found in the intestines, Bifidobacteria are also commonly included in probiotic supplements. They help in breaking down complex carbohydrates and promoting a healthy balance of gut flora.

Saccharomyces boulardii: This is a yeast probiotic that can help maintain a healthy balance of bacteria in the gut. It's often used to prevent or treat diarrhoea caused by antibiotics or infections.

Streptococcus thermophilus: Like Lactobacillus, this bacterium is often found in yogurt and helps support digestion and gut health.

While probiotics have been studied for their potential benefits in preventing various diseases, including colon cancer, the evidence is still emerging and not definitive. However, probiotics do play a crucial role in maintaining overall gut health and can contribute to the prevention of certain gastrointestinal issues such as diarrhoea, irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD).

The mechanisms by which probiotics contribute to health are multifaceted. They can help by:

Maintaining gut flora balance: Probiotics help maintain a healthy balance of bacteria in the gut, which is essential for proper digestion and nutrient absorption.

Strengthening the gut barrier: Probiotics can enhance the integrity of the gut barrier, preventing harmful substances from crossing into the bloodstream and reducing inflammation.

Modulating the immune system: Probiotics interact with the immune system in the gut, helping to regulate immune responses and reduce inflammation.

Producing beneficial compounds: Some probiotics produce short-chain fatty acids and other compounds that support gut health and may have anti-inflammatory effects.

While more research is needed to fully understand the role of probiotics in preventing specific diseases like colon cancer, maintaining a diverse and balanced gut microbiome through a combination of probiotic-rich foods and a healthy diet is generally considered beneficial for overall health.

Having explained the above about microbiome and gut bacteria let us now go from nutrition into food science.  

We can now use our knowledge in simple food science to make our own yogurt at home. We can of course buy ready made yogurt from the food shop or supermarket. But they are very expensive. So we shall make our own. 

First we need to buy a cup of ready-made yogurt with at least two types of milk bacteria inside, namely, Lactobacillus bulgaricus and Streptococcus thermophilus. 

This is how to make our own yogurt.

Bring the fresh milk home and gently boil the milk in a pot for about 1 – 2 minutes under low fire. 

Next, let the milk cool to almost room temperature. Once cooled, use a clean spoon to add 1 - 2 tablespoons of the fresh yogurt into the cooled milk and stir.

Do NOT stir the cup of yogurt into the boiled milk when the milk is still hot. The heat will kill the milk bacteria, and yogurt cannot be formed. Cool it down first to near room temperature before stirring in 1 – 2 tablespoons of the fresh yogurt as a starter.
  

Then cover the pot of milk to prevent other bacteria entering into the milk. Leave overnight in a warm place. Do not put the pot of milk inside the refrigerator as yet. Leave it covered in a warm place in the kitchen so that the live milk bacteria as a starter from the cup of fresh yogurt can ferment the milk. 

Once yogurt has been formed only then you should keep it inside the refrigerator, but not before that, else yogurt will not be formed from the milk if it is too cold inside a refrigerator. After the yogurt is formed, you need to put it inside the refrigerator to prevent other bacteria from entering.

The next morning about 8 – 10 hours later after stirring in the starter yoghurt, all the milk should be converted into yogurt by the bacteria in the yogurt you bought.  If the milk has not turned into yogurt within 8 – 10 hours, leave it for another 4 hours. If the milk still has not turned into yogurt, then the starter yogurt you bought from the supermarket did not contain live bacteria inside.  In that case throw it away and try again using fresh milk and another different cup of yogurt. Make sure the milk and the cultured yogurt you bought have not exceeded their expiry dates else the bacteria were not there.

Now scoop up a bowl of the home-made yogurt and add in 1 -2 spoonfuls of sweetened condensed milk together with some fresh fruits or canned peaches, apricots, and pineapples with its syrup.  The canned fruits with the syrup or freshly cut fruits can be kept cold in a refrigerator beforehand.

Your home-made yogurt will save you a lot of money instead of buying many cups of them from the supermarket. Yogurt eaten with canned fruits and
syrup inside is quite tasty and very nutritious. You can make as many pots of home-made yogurt as you want cheaply by using the Lactobacillus bulgaricus and Streptococcus thermophilus present in the manufactured yogurt to ferment the lactose (milk sugar) into lactic acid.  While the overall protein content remains relatively similar between milk and yogurt, the biological value (BV) of the protein may change slightly due to the fermentation process, but still contains high-quality protein with essential amino acids, similar to milk.

Some studies suggest that the BV of protein in yogurt may be slightly higher than that of milk due to the fermentation process, which can make the protein more easily digestible for some individuals. Additionally, yogurt contains probiotics, which can benefit gut health.

In summary, while there may be minor changes in the biological value, yogurt remains a nutritious source of protein with valuable health benefits.

I hope my recipe as a food scientist and a food quality controller and as a nutritionist helps. But other clinicians with an MD may not know this.