Determine Nutrition Facts

Hello, guys! What do you think about my last post? Do you like it? Before we start this session, there is a video about how Western people manage their daily milk processing with high technology.

https://www.youtube.com/watch?v=hmtDydK_K9g

Well, now I want to share with you about how to check the nutrition facts inside foods. Enjoy!

Water

First of all, let's check the water content by heating the food. The heating should be in 100°C or 212°F and the heating should not last until the mass become constant. This proved that all of the water has been evaporated. You should weigh the mass of the food before and after heating. So that you can subtract both masses and have the mass of the water content. Calculate the percentage by dividing the mass of the water and the mass of the food before heating, then multiple by 100%. After knowing the water content, we could find the protein, fat, mineral and carbohydrate that the food contains.

Protein

The protein content could be found in traditional way or modern way.

In traditional way, we could use Kjeldahl method. The method consists of three steps:

1. Digestion of the sample in sulphuric acid with a catalyst. The nitrogen contained in the sample is converted to ammonia; ammonium sulphate being formed.
2. Distillation of ammonia released from ammonium sulphate by addition of an excess of sodium hydroxide; ammonia being trapped in a trapping solution (sulphuric acid).
3. Back-titration of the excess of the trapping solution. 

(http://web.vscht.cz/~kohoutkj/ENG/LAB_NITROGEN_Determination_2012.pdf)

In modern way, we could use Lowry method. The principle behind the Lowry method of determining protein concentrations lies in the reactivity of the peptide nitrogen[s] with the copper [II] ions under alkaline conditions and the subsequent reduction of the Folin- Ciocalteay phosphomolybdic phosphotungstic acid to heteropolymolybdenum blue by the copper-catalyzed oxidation of aromatic acids [Dunn, 13]. The Lowry method is sensitive to pH changes and therefore the pH of assay solution should be maintained at 10 - 10.5. The Lowry method is sensitive to low concentrations of protein. Dunn [1992] suggests concentrations ranging from 0.10 - 2 mg of protein per ml while Price [1996] suggests concentrations of 0.005 - 0.10 mg of protein per ml. The major disadvantage of the Lowry method is the narrow pH range within which it is accurate. However, we will be using very small volumes of sample, which will have little or no effect on pH of the reactionmixture.  A variety of compounds will interfere with the Lowry procedure. These include some amino acid derivatives, certain buffers, drugs, lipids, sugars, salts, nucleic acids and sulphydryl reagents [Dunn, 1992]. Price [1996] notes that ammonium ions, zwitter ionic buffers, nonionic buffers and thiol compounds may also interfere with the Lowry reaction. These substances should be removed or diluted before running Lowry assays. 

(http://www.srmuniv.ac.in/sites/default/files/files/BT-0413-BioseparationTechnologyLaboratory.pdf)

Fat

In knowing the fat content, you can react the food with base aqueous solution.

The reaction should be:

There are several foods as examples, such as coconut, soybean and corn oil.

Coconut

1. Extract the fat of the coconut then make it into coconut milk.
2. Heat the coconut milk until the whole water evaporated.
3. Calculate the fat content. 

Soybean

1. Crack soybean.
2. Heated to between 60 and 88 °C (140–190 °F).
3. Rolled into flakes.
4. Solvent extracted using hexane.
5. Calculate the fat content.

Corn Oil

1. Extract the corn oil from the part between kernel and cob.
2. Solvent extract using hexane.
3. Calculate the fat content.

Mineral

To determine the mineral content, you need to use the destructive test. So, the foods are no longer able to be consumed. The foods need to be burnt to ashes. Calculate the mineral content from the ashes.

Carbohydrate

Food content of carbohydrate can be calculated by this method.

100% - (total protein + total fat + total mineral + total water)

So that's how we determine the contents of food we consume every single day. 

As we know, every airlines have many passengers each day and they have to serve at least one meal for each passenger in every flight. Have you ever wonder how they prepare the meals, how to keep it fresh and how they deliver all of the meals? These videos below will show you.

  

https://www.youtube.com/watch?v=yex-WMaJTjg

https://www.youtube.com/watch?v=mD8yP0db2Eg