Processing Techniques Ensure Product Consistency
by Heather Granato
A consumer stops at a high-end bakery on his way home from work and picks up a few chocolate chip cookies as a treat for the family. Then after dinner, his disappointed son discovers his cookie has no chips, while his daughters cookie is packed with chips. Perhaps they can split the cookies, ensuring fair chip distribution. Obvious problem, obvious solutionbut a likely lost customer for the bakery.
What if this problem occurred with the familys multivitamins? Not such an obvious problem, as nutrient deficiencies and high dosages arent necessarily immediately visible. However, it is a problem if the children receive toxic doses of iron from their multi or dad received no coenzyme Q10 (CoQ10) to offset deficiencies caused by his blood pressure medication. These are quality control problems that can compromise consumer health.
Avoiding this problem in nutrient delivery means careful control of the blending and processing steps in production. Without proper blending, the best conceived product may be a failure in terms of ingredient quality claims, taste and dispersion, said Eric Barber, national sales manager with Lawrenceville, Ga.-based Valentine Enterprises. Proper know-how must be applied to each specific product, which should be tested for uniformity of content on an ongoing basis.
Doug Gillespie, president of Pro-Form Laboratories in Orinda, Calif., agreed with this assessment. Blending is a critical step to the efficacy of a finished product, he said. It takes an experienced batch maker to be able to make the proper adjustments and turn out the same product day after day.
There is a range of techniques available to processors to ensure the final capsules, tablets or packets are homogenous, highquality products. Every ingredient has to be in every part of the blend in order for the final product to contain what it is supposed to have, said John Blanco, sales and marketing director for AnMar International in Bridgeport, Conn. The bottom line is to know what factors will deteriorate your materials and shorten shelf life, and avoid that result.
Making a high-quality finished product starts with ingredient selection, and continues through processing and delivery form before reaching the consumer. Each part of the process is designed to combine the ingredients into forms that will not adversely interact, but instead deliver quality nutrition to a consumer. Think about this process as a modular approach, said Ram Chaudhari, Ph.D., senior executive vice president at Schenectady, N.Y.-based Fortitech. You start with a group of ingredients and combine them to become less reactive and make two or three modules. Then you combine those for a finished product that meets the homogenicity test.
While every ingredient has its own dossier of physical properties and potential interactions, primary considerations include particle size, moisture content, ingredient percentages and bulk density. Each must be addressed individually before the formula makes it into the blender.
Matching particle sizes of different ingredients ensures consistent distribution in a blend and contributes to stabilizing densities and moisture content. It is unusual for all the ingredients in a blend to be the same size. However, manufacturers can also work with their suppliers to attempt to ensure consistent particle size among ingredients. We stipulate and test for correct mesh size from our suppliers to ensure ingredient uniformity, said Dave Sandoval, president of Long Beach, Calif.- based Organic by Nature. This lowers the impaction rate and need for processing.
In many cases, though, the materials undergo some type of processing to ensure size conformity and adhesion quality. Two primary processing techniques that affect particle size are milling and granulation.
Milling (grinding) is a fairly straightforward procedure, often used with botanical ingredients to break down larger particles into a specific smaller size. Material passes through cutting chambers and is forced through mesh or perforated screens, resizing larger materials to a smaller set standard.
On the other end, granulation increases particle size by combining ingredients. Wet stage granulation (or agglomeration) uses a fluid (water or alcohol) to stick the powder ingredients together, forming larger, more porous combinations. The solution is then heated to dry out the particles, which remain in their new matrix. Dry granulation uses mechanical force to compact the ingredients. Granules tend to flow better, are less dusty and dissolve more quickly than a combination of fine powders. The best agglomerate adds nothing new to the product and retains the original moisture range, as well as improves the dispersion, uniformity and density of the finished product, Barber said. Granulation can be used prior to blending, or after blending, depending on the formula needs and the desired delivery form.
Wet granulation obviously affects moisture content, which is itself a processing consideration. This issue encompasses the moisture content of individual materials and their hydroscopicitywater affinity. In working with whole food ingredients, such as botanicals, moisture levels can vary depending on the time of year, growing conditions, harvesting techniques and storage situation. Therefore, working with contract manufacturers that have experience in working with such ingredients can take the guesswork out of how to measure and account for variations in moisture content.
An ingredients propensity for absorbing moisture from other ingredients must also be accounted for in evaluating moisture issues. Coenzyme Q10 (CoQ10) is an example of a hydroscopic particle often used in small quantities in formulas, Sandoval said. If you just add a small amount into a formula, it would likely clump with other ingredients and not disperse, he said. Instead, you dilute it into another ingredient using a small quantity Kelsinator or dispersion blender. This dispersion ensures the CoQ10 does not take on additional moisture during blending, thus forming clumps that could affect the finished flow.
Dispersion is commonly used not only for ingredients with high moisture content, but also for those added in microgram quantities to a formula. If an active ingredient is very small compared to the total weight, steps must be taken to ensure the active will be found in each dosage at an acceptable level, said Gary Callahan, vice president of technical and regulatory affairs for City of Industry, Calif.-based Best Formulas. To ensure a minute quantity of a vitamin, for example, is spread throughout a large blending run, the ingredient is dissolved into formula and then agglomerated to add to the total mix. This solubilized combination formula is then a single module in the assembly of the formula moving forward.
Such modules are combined with individual nutrients, and every portion of the mix has a different weight and density. Formulators must consider the natural propensity of ingredients to stratify in solution. The goal of blending is to combine the ingredients so they have uniform dispersion, without overblending, where ingredients begin to settle out. It is critical to pay attention to blending sequence and blending times, Gillespie said. Densities are always a battle. Also, if you under blend or over blend, you can have a product that does not have a homogenous mix. You may have hot spots that contain too much of an ingredient or cold spots that do not contain enough.
The type of materials and final delivery form influences the type of blender. In the nutraceutical industry, there is a range of options. V blenders are possibly the most common, in which materials are tumbled together and separated into the V arms, often using a intensifier bar to further break up the material. Other options include cone blenders, drum blenders and ribbon blenders. Several contract manufacturers noted they have their blenders custom designed and built to meet in-house specifications and SOPs (standard operating procedures).
A well-rounded company must have several types of blending and processing equipment, Callahan said. Most common would be a tumble type blender, a ribbon type blender and a high shear type blender. Additional equipment such as sifters, grinders and granulators must also be available to allow for various types of processing to achieve the desired specification of the blended product.
Ultimately, blending is a vital step in the production process. Attention to detail ensures quality materials ultimately deliver what is promised to the consumer. There is no simple answer, Chaudhari said, and no substitute for experience to learn the tricks of the trade.