Butter is a premium dairy product. Failure to control the butter defects can lead to some serious consequences such as food poisoning when the consumer uses the defective butter.
Before releasing the butter to the market for sale, a team of competent judges conducts a series of tests to grade it. They carry out organoleptic tests to score for flavor, texture, color, and shape.
Different countries have different demands for these quality parameters. However, the evaluation methods remain fairly uniform from one country to the next.
Factors to consider when evaluating butter defects:
- Appearance; color and package
- Body and texture; consistency
Defects in appearance
The judges check for color and uniformity. Here are some of the butter defects related to appearance and how to correct them
1. Free moisture/leaky butter
The butter is considered to be leaky if the trier exhibits visible droplets. Free moisture predisposes the butter to microbial attack.
Free moisture may result from poor kneading of the butter, incomplete salt dissolution, or working the butter after it has already firmed up.
2. Mottled butter
Mottling occurs when there are tiny, evenly distributed discolorations that result from uneven and insufficient salt dispersion in butter.
3. Streaky butter
You notice this defect when you cut the butter and there are bands of different colors. This defect is common with the butter from a continuous butter making process due to the short working time involved.
It is common in butter with high iodine value but may also arise due to mixing of two batches that have different colors.
4. Oily butter
This happens when you notice droplets of butter oil after cutting the butter. This defect may occur due to the application of intensive vacuuming during kneading.
You can prevent this defect by reducing the vacuum during butter working. Too soft cream has a higher risk of producing an oily butter.
5. Moldy butter
You observe a visible mold growth on the butter or the wrapping material. Faulty packaging may provide access to the inner parts of the butter and make it possible for the molds to grow.
This defect affects the quality of the butter since the moldy appearance; the smell and the taste are unwelcoming. Furthermore, lipolytic activity may lead to rancidity rendering the butter inconsumable.
The molds may be transferred from the packaging material, through the air, the utensils, or even the butter handling equipment.
6. Open butter
When you cut the butter, you will notice small notches on the cut surface. This defect results from overworking the butter. The butter sticks to the churn and is torn as it rotates.
It may also result due to too much air in the butter as a result of insufficient vacuuming.
7. Foreign particles in butter
Occasionally, you may find foreign materials such as metals, wood, hair, or glass in the butter. To avoid these, ensure the working environment is clean.
Also, ensure that the spatula you use for working the butter is not split to avoid splinters in the butter.
Butter defects related to consistency
High quality butter should have a firm closely-knit texture. Consistency (body and texture) of butter borrows a lot from the physical properties of the butter.
These properties depend upon butter composition, structure of fat globules, rate of crystallization in cream and butter, amount of liquid fat and the size of the fat crystals in the butter.
The butter defects related to consistency include:
1. Crumbly butter
The fat particles are non-cohesive; they do not stick together. The butter is dry and readily falls apart when you apply pressure to it. This defect occurs due to rapid cooling or too hard fat globules.
2. Greasy butter
Characterized by extreme smoothness and easy melting in the mouth. It is also sticky, soft, and often oily.
3. Gummy butter
Sticks to the roof of the mouth due to high percentage of high melting point glycerides.
4. Mealy/grainy butter
Noticeable grains in the butter. This happens when you do not properly neutralize the high acid in the cream with lime.
5. Short butter
Such butter lacks plasticity and waxiness. It is not easy to spread as it is brittle and breaks easily.
6. Gritty butter
Happens when there is undissolved salt in the butter.
Butter defects associated with the flavor
Appearance and consistency accounts for half the butter score and flavor the other half. High quality butter should have a clean, sweet, pleasant taste and a delicate aroma. It should not have a pronounced taste and odor.
The flavor defects include:
1. Acidic flavor
Results from high acid or over ripened cream. It has a sharp sour taste.
2. Malty flavor
The butter tastes like wine or grape due to the growth of Lactococcus lactis subspp Multigenes, which acts on the curd to produce citric acid associated with the wine flavor.
3. Cheesy flavor
Proteolytic enzymes split the casein in cream or butter.
4. Rancid flavor
Characterized by a strong, bitter and soapy flavor. It results from hydrolysis of fats by lipases.
5. Tallowy flavor
Happens when the unsaturated fatty acids in milk undergo oxidation in the presence of metals (copper and/or iron). The oxidation process produces the taste and odor of lard (pork fat).
6. Yeasty flavor
Occurs due to the byproducts from yeast growth. They undergo lipolytic and proteolytic activity.
7. Alkaline flavor
Occurs if you add too much neutralizer to the cream. The butter ends up tasting like soap and bitter with a slimy feel.