Better understanding grass-fed vs. grain-fed beef

2009-03-28T00:00:00Z 2011-01-11T20:35:57Z Better understanding grass-fed vs. grain-fed beefBy Ryan Cox, Ph.D., Extension Meats Specialist Minnesota Farm Guide

University of Minnesota Beef Team

In a market where each purchase decision is met with increased scrutiny, consumers are demanding more specific characteristics from the meat items that they purchase.

Niche marketing has become more prevalent as processors attempt to meet the demands of the evolving consumer. In addition to traditional meat items, demand has increased in the past decade for locally produced, grass-fed, natural and organic products.

Considering the challenging economic climate as of late, consumer demand has decreased slightly for the more expensive of the latter, organic products. However, demand remains fairly constant for natural and grass-fed products, an indicator that these products may represent more than just a trend.

There is a perpetual debate in existence over the meaning of the claim “natural” for meat products with concerns over factors in both animal production and meat processing methods.

Perhaps more straightforward is the grass-fed claim, which typically indicates that the animal did not consume any significant amount of grain in the finishing phase, and diet was primarily forage.

In the history of the United States, we have commonly had an abundance of corn, and thus livestock was finished using this high energy source. High energy finishing systems are what give beef the white fat and characteristic corn fed flavor.

These are characteristics that American consumer have become accustomed to when evaluating the quality of beef. It is commonly forgotten that this method of finishing cattle is not characteristic for other parts of the world, including our neighbors as close as South America. For these consumers, beef has an altogether different flavor, as these animals are finished primarily on forage, and thus the grass-fed beef flavor is more ideal.

So what is it exactly that makes grass-fed beef different than traditional grain-fed beef?

Carcass weights of forage-finished beef cattle are lower than those in concentrate-finished carcasses. This is largely because forage-finished beef cattle do not receive as much total energy in the diet as the cattle finished on concentrate. Since USDA yield grade relates the percent of saleable lean within a carcass, and a higher numerical yield grade indicates a higher percentage of fat, one of the claims that producers of forage-finished beef make is a lower overall yield grade in the carcass. Research has also documented lower USDA yield grades in forage-finished beef carcasses.

Tenderness of forage-finished beef is extremely variable. One of the traditionally used reasons for not producing forage-finished beef is that it produces a less tender product as measured by Warner-Bratzler shear values and sensory panels. However, conflicting research indicates that no tenderness differences between forage-finished and grain-finished beef exist.

It is important to keep in mind that beef tenderness is an attribute that is affected by many different factors. Among these factors are animal age, sex, biological type, muscle location, connective tissue cross-linking, muscle fiber contractile state and feeding regimen.

There has been conflicting data concerning the flavor acceptability of forage-finished beef. A large amount of research indicates that forage-finished beef has a grassy or milky flavor that is sometimes described as an off-flavor or a more intense flavor. The distinguishing flavor of forage-finished beef is attributed to the beef fat.

Compounds referred to as diterpenoids are responsible for the off-flavor's source. These compounds are derived from the action of ruminal microorganisms as they break down chlorophyll. One other explanation of the off flavor in forage-finished beef is due to the higher concentration of unsaturated fatty acids.

Conversely, there has been research that indicates that there is no sensory flavor difference between forage-finished and grain-finished beef. There are several possible explanations for the different outcomes of the different studies concerning forage-finished beef. The amount of time on forage is certainly a major factor in the flavor development of the beef, specifically in the deposition of the flavorful fat.

Similar to the issues of beef flavor and tenderness, conflicting data exists on the color of lean in forage-finished beef as compared to grain-finished beef.

Research indicates that the lean color of forage-finished beef is darker than grain-finished beef and conflicting research has also indicated that there is no significant difference in the lean color of forage-finished and grain-finished beef.

Of less debate is the appearance of the beef fat. The appearance of bovine fat is primarily affected by the absorbance of carotene and hemoglobin derivatives, the reflectance, transmittance, and fluorescence of lipids, and the reflectance and fluorescence of non-lipid components. The research concerning fat color generally agrees that forage-finished beef fat has a more yellow or creamy color than the whiter concentrate-finished beef fat color. It has been found, however, that grain supplementation of forage-finished cattle prior to slaughter reduces tissue concentration of beta-carotene, thus reducing the amount of yellow color found in the fat.

As increased levels of forage are consumed, animal fats tend to increase in their composition of unsaturated fatty acids. There is a mass of research supporting the benefits of unsaturated fats in the human diet including benefits to heart health. The group of fatty acids referred to as Omega-3 fatty acids are of particular interest to many forage-finished beef producers and they are in higher abundance in forage-finished beef.

This type of fatty acid provides many health benefits to humans, including the clinical development of young children, vision development, brain composition and structure, membrane structure and chronic disease prevention.

Health considerations aside, there are several characteristics of unsaturated fats that are of interest to meat processors. Unsaturated fats tend to be more like oils and less like solid fats, and thus a higher occurrence of unsaturation in a meat fat will produce a softer fat.

For fresh meats, soft fat is undesirable as it is detrimental to product appearance and texture. For processed meats, there are other considerations. Soft fat in bacon makes it more difficult to slice and maintain shape. For emulsified meats such as frankfurters and bologna, soft fat will degrade texture and make a greasy product.

Beyond texture and appearance, the nature of fat has a large effect on meat degradation. Unsaturated fats are more susceptible to oxidation, or rancidity which means that meats with a higher percentage of unsaturated fats will tend to have a shorter shelf life. These meats will produce undesirable flavors and colors in a shorter period of time.

As we move forward in answering the needs of the evolving consumer, it is important to understand the nature of the products that we are marketing. Grass-fed beef certainly appears to have a presence in our current market, and may for years to come. Knowing the difference between this type of beef and our traditional beef products will continue to be an important factor in answering our industry's needs.

Copyright 2015 Minnesota Farm Guide. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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