Comprehensive Grade Analysis Discussion (Educational)

Grade analysis discussion

This discussion is designed to help understand the bases for quality analysis of shea butter. The certificate of analysis is not included in this document.  The document discusses and reference to the laboratory values reported in the certificate of analysis.   In this document the test sample is referred to as sample batch #1.

CERTIFICATE OF ANALYSIS

Presented by

The American Shea Butter Institute

Segments from Sample Batch # 1

Report are Discussed

I. INTRODUCTION

II. MICROBIOLOGICAL ANALYSIS

III. METAL CONTENT

(A). Metals

(B). Metal Content of Sample  Batch #1

(C). Source of Iron and Other Metals

(D). Water as a Major Source for Metals

IV. PEROXIDE LEVEL

Storage Conditions That Promote Peroxide Formation

Efforts to Retard or Prevent Peroxide Formation

Effect of Storage and Age on peroxide production and thus quality

Conditions for best Outcome during storage   (HALT)

Monitoring the Effectiveness of Sample  Batch #1 Storage Environment

V. FREE FATTY ACIDS

(1). Factors Known to Degrade and Destroy Shea Butter

IV. FATTY ACID PROFILE

VII. SHELF LIFE

VIII. RANCIDITY

Oxidative Rancidity

Biological Oxidative Rancidity

Metals Induced Rancidity

Hydrolytic Rancidity and High Temperatures

Oxygen and Spontaneous Decay

IX. BIOACTIVE FRACTION

X. SUMMARY

Recommended Uses for Grade D Shea Butter

I. INTRODUCTION

The information below will provide assistance in understanding the laboratory results presented in the Certificate of Analysis. The information explains the lab test results in simple, easy to understand terms. In addition, ASBI has made recommendations to help maintain and improve the quality of future productions.

This information is most valuable for the production team. The production team can improve the quality of the butter by adopting and implementing the recommendations contained within this report.

II. MICROBIOLOGICAL ANALYSIS

Microbial Contamination can be potentially harmful to the end user. The personal care industry strongly opposes the use of microbial contaminated shea butter.   The most common microbial contaminants found in unrefined shea butter are mold, yeast, and fungi. The most dangerous microbial contamination comes from the Coliform organisms, such as E.coli, Salmonella, Shigella, etc. The presence of Coliform organisms is indicative of unsanitary conditions during preparation.   Whenever coliforms are found, the entire operation must be shutdown until the source of these pathogens are identified and corrected

Any shea butter found to contain microbial contamination automatically receives a quality Grade of F.  Shea Butter with microbial contamination of any type is not recommended for use in the personal care industry.

We performed over a half of dozen tests on Sample Batch #1 in search for microbial contamination. We are pleased to report Sample Batch #1 does not contain any evidence of Coliform mold, yeast or fungal contamination.

III. METAL CONTENT

We test for metal content in shea butter for a number of reasons. Metal contamination of any kind increases free fatty acid formation, increases peroxide formation, increases rancidity, reduces shelf life, and reduces the quality grade of shea butter.  For that reason every effort must be made to reduce or prevent metal of any kind in shea butter.

(A). Metals

Heavy metals such as lead and mercury, in addition to promoting rancidity, can be potentially harmful to the health and well being of the end user. Therefore any shea butter found to contain lead or mercury automatically receives a quality grade of F, and is not recommended for use in the personal care industry.

(B). Metal Content of Sample Batch #1 Shea Butter

When we studied the metallic content of Sample Batch #1 shea butter neither lead nor mercury were found. This observation is considered excellent. When we looked for other metals we found iron at 2.0 mg per kg.  This is considered this value borderline poor.  We like to see the iron content below 2 mg/kg. The high iron content in Sample Batch #1 is a major contributes to the high peroxide of 5.61 millequivalents per kg.

(C). Source of Iron and Other Metals

To reduce iron content in shea butter make sure all utensils, pots and other instruments are made of stainless steel, or wood or plastic. The mechanical crushing and milling equipment must be stainless steel.  Check to make sure that the water used does not have high iron content.

(D). Water as a Major Source for Metals

The importance of water quality used in shea butter production is often overlooked.  Water with high metallic content will produce poor quality shea butter.  The major sources of water in communities where shea butter is made are well water, rainwater, and river water. Obviously, well water is preferred over rain or river water. Below are the most common metals found in samples of well water through out East and West Africa. The use of water containing one or more of the agents listed below will guarantee poor quality shea butter.

Deionized water is the best water for production of high quality shea butter. Unfortunately, deionized water is not readily available in shea butter producing communities.  When using well water, it is strongly recommended to test water for its metallic content.  You send a sample of water for metallic analysis to ASBI lab or a lab of your choice.  If laboratory results reveal the water has a high metallic content you must identify another water source with less metal. Sometimes a good micro-filtration system can reduce metallic content.   Increasingly more and more processors are following ASBI recommendation by   performing waterless extraction and processing of shea nuts to shea butter.

(E). Proper equipment maintenance between extractions reduces metal oxides formations

The best equipment and utensils for shea butter extraction should be  made of stainless steel, plastic or wood.

Equipment and utensils made of any other material is likely to increase the metallic content of shea butter. Increased metallic content means lower quality.   Maintenance of good clean equipment also helps to reduce metal oxides formation on the surface of equipment between extractions.  To that end, when extraction is completed, all equipment, used in the extraction, must be washed with soap and water, hand dried then carefully and completely oiled down, with fresh shea butter or some other clean vegetable oil.

Between extractions, oiled equipment and utensils should be kept in a room where the temperature is controlled and maintained at 70 degree Fahrenheit or less.

When ready for the next extraction, remove the equipment and utensils from the temperature controlled room; again wash all equipment and utensils with warm soap and water then rinse several times with clean water to remove any residual oil that may have gone rancid during storage.

VI. PEROXIDE LEVEL

The peroxide level in Sample Batch #1 Shea butter was found at 5.61meq/kg.  This value is too high; the peroxide value should not exceed 2 meq per kg, (two millequivalents per kg).

On the day of extraction, the peroxide level is always zero or close to zero.  For the peroxide level to rise from zero in July of  to 5.61 meq per kg by August   suggest serious corrections must be made in one or more extraction steps or in post extraction management. The rate of peroxide formation by Sample Batch #1 is eight times faster than the preferred rate of 0.5 meq per kg. This process profoundly limits the shelf life for Sample Batch #1.

To improve the quality grade of shea butter it is important that you make every effort to identify those factors that may cause a rapid rise in peroxide.

Below are suggestions to Retard or Prevent Peroxide Formation

1.    Use only plastic, wood or stainless steel utensils and equipment during (1) fruit / nut preparation, (2) oil extraction, (3) packaging, (4) storage and (5) shipping of Shea product.

2.    All equipment, utensils, pots and bowls must be plastic, wood or stainless steel; all others are unacceptable for production of high quality shea butter.

3.    As mentioned early, metal of any type will promote peroxide formation

4.    One fundamental law in shea butter preparation is NEVER MIX NEW FRESHLY PREPARED SHEA BUTTER WITH OLD BUTTER. One bad apple spoils the barrel.

5.    Inappropriate post extraction storage environment is a major cause for peroxide formation. Once shea butter extraction is completed, make every effort to keep the butter in airtight containers stored in a dark, cool and dry area.

6.    Maintain an aseptic storage environment.

7.    Maintain aseptic practices when transferring Shea butter from one storage container to another

8.    Do not use storage and shipping containers made of materials other than stainless steel, plastic or wood.

9.    Always thoroughly wash, where possible steam clean, and thoroughly dry all storage containers prior to use. It is absolutely imperative that these containers are clean and well dried before filling with shea butter.

10. In the post extraction period, there exist certain factors that must be understood to better manage shea butter in the out months..  Under improper storage conditions, see halt below, fatty acids will react with oxygen to form peroxides. The common peroxide forming fatty acids are;

1). Alpha Linolenic

2). Linoleic

3). Oleic

4). Eicosenoic

5). Gamma Linolenic

East African shea butter has a larger content of peroxide forming acids when compared with West African shea butter. Further, East African shea butter has less antioxidant than West African shea butter.  This fact explains why East African shea butter produce peroxides faster than West African Shea Butter.

The term HALT defines the fundamental law for shea butter storage.

Humidity (low humidity /dry)

Air: Containers should be closed airtight.

L Light is undesirable. Shea butter should be stored in a dark area

T Storage temperature should 70 F or lower. Higher temperatures promote peroxide formation.

Effect of Storage on peroxide production and thus quality

All biological materials are undergoing continuous decay. This fact explains why quality is lost with age.  The decay process occurs even in the most ideal storage conditions. Decay is oxygen driven. Oxygen must be present for biological material to decay. Therefore keeping the containers sealed airtight prevents oxygen exchange, thereby reduces decay over a given period of time.

1. Avoid opening and closing of storage containers.  Once the butter is rancid you have lost serious capital.

2. Quality decreases as the butter ages.

3. Properly prepared shea butter free of microbial contamination, metal contamination, and moisture contamination, properly stored in air tight container(s) in a climate controlled storage environment should hold its quality value for well over a year.

The graph below shows shea butter that was stored at various temperatures for 6 months and the peroxide content determined monthly from each temperature point.

The results show as the temperature increases from 70° to 90° degrees, there is a corresponding increase in the rate of peroxide formation.   The ideal storage temperature is noted as 70° F. This finding shows the preferred rate of peroxide formation is 0.25 – 0.50 meq per kg per month.

Monitoring the Effectiveness of the Storage Environment

The two parameters that give the best indication regarding optimum storage environment are FFA and peroxide.  To monitor the effectiveness of storage conditions you should obtain a monthly peroxide valve and a monthly FFA value.

(5). In an Ideal environment, for a pure, properly prepared, uncontaminated shea butter, peroxide changes should be less that 0.5 meq per kg per month, while FFA changes less than 1% per month.

If the change in peroxide is greater than 0.5 meq per month, the storage environment is inappropriate or the shea butter has serious issues such as metal contamination, microbial contamination, or other undesirables such as the improper storage containers, storage temperature maybe to high, storage containers may not be air tight. It is important to make every effort to determine the cause of a rapid rise in peroxide value during storage.

V. FREE FATTY ACIDS

The amount of free fatty acids present in a given Shea Butter tells us the degree of destruction and digestion that has occurred.  The presence of free fatty acids above 2% is indicative of significant destruction and breakdown of important ingredients, especially the Triglyceride.

For this reason the higher quality rating is awarded to those butters with the free fatty acids below 2 %. During quality evaluation, the highest possible score a given shea butter can earn is a total of 139 quality points. The FFA contribution to the 139 quality points can be as much as  25 points. Those butters with a FFA of 2% or less are awarded the maximum of 25points. Butters with FFA of 6% or greater are awarded only 5 points.  That shea butter with FFA between 2% and 6% are awarded a point value between 25 and 5 points.  The FFA contribution in Sample Batch #1 was found to be 4.17 %, which is considered poor.

Destruction of the natural integrity of Shea Butter to liberate FFA

There are several parameters known to increase Free Fatty Acids.  These conditions occur in each of the three phases of extraction, namely:

• The pre – extraction phase
• The heating/cooking phase of extraction
• The post extraction phase

(A). Pre extraction phase: Prolonged digestion time is the major pre-extraction contributor to elevated FFA.

In the traditional extract method the time period between the crushing-milling step and heating step is referred to as the DIGESTION TIME. .

• Care must be taken to avoid a prolonged DIGESTION TIME.
• The ideal DIGESTION TIME is 0 -1 hour.
• Never allow milled paste to sit overnight.
• Prolonged digestion time results in marked increase in FFA
• When an oilseed cell is ruptured during crushing-milling step a large pool of digestive enzymes is released.
• These enzymes digest valuable ingredients in the oil.
• This digestion is optimal at temperature range 30 – 60° C.
• Temperatures above 60° C inactivate the digestive enzymes.
• The inactivation temperature is achieved during heating step.

This information should help you understand why the digestion time (defined earlier) is a quality-determining step.

The digestive enzymes mentioned above are cited below.

(B). Factors that increase Free Fatty acids during Heating/Cooking phase:

• Prolong digestion time results in increased FFA content.
• Inappropriate heating temperature i.e., too high; or too low. Ideal heating temperature is 90° C,
• Using hard water for processing. Hard water has a higher metal content. Metals serve as catalyst and increase rate of triglyceride destruction therefore increasing FFA content

(C). Factors that increase Free Fatty acids in the Post extraction phase:

• Storage temperature above 70° F
• Moisture content, greater than 1%
• Storage containers opened to air,
• Storage containers exposed to sunlight.
• Microbial contamination

VI. FATTY ACID PROFILE

The fatty acid profile for Sample Batch #1 is within acceptable limits. The Oleic acid / Stearic acid ratio was within normal limits for East African shea butter. . The Palmitic acid/ Oleic acid ratio was within normal limits. To that end, there was no indication for Triglyceride profile; therefore, test performed

VII. SHELF LIFE

Shelf life is considered the amount of time before a given shea butter is rancid.

We consider a shea butter is rancid once the peroxide level reaches 6-meq/per kg.  The amount of time required for a given shea butter to go rancid is dependent on a number of intrinsic and extrinsic factors. Extrinsic factors responsible for rancidity are discussed in details below. Each batch of unrefined shea butter has its own unique rate of peroxide formation and thus, its own unique shelf life.

Once extraction is completed, the intrinsic factors that promote rancidity are listed below.

Metal content

Insoluble debris

Light expose

Storage temperature

The Size of The Bioactive Fraction For Various Oil

Oil

Baby Oil

Mineral Oil

Olive Oil

Sesame Oil

Soy Oil

Maize Germ Oil

Refined Shea Butter

Argan oil

Avocado

Low quality Unrefined

Sample  Batch #1

Wheat Germ Oil

Higher quality Unrefined

Certified Premium Grade A

Summary of major problems

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