Grape Residues or Pomace as a Meat Preservative?

Today’s post looks at the remnants of grape bits that might otherwise be tossed away after pressing, and one possible new use for them.

So, wine industry residues:  can they be used as a meat preservative?  (eww?)

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Meat is a common item on the dinner plate of many people around the globe.  So much so, that the food industry is constantly trying to find new and better ways to preserve meat products in order to increase the shelf life and improve quality and food safety.  Chicken meat, in particular, is prone to severe degradation if not properly processed and stored.  If improperly processed/stored, chicken meat often undergoes lipid oxidation, which after a microbial deterioration, results in the loss of quality and renders the food unfit for consumption (without risking major health issues).

Meat processing plants will often use synthetic additives that contain antioxidant properties, in order to combat this issue of degradation caused by oxidation.  Due to the potential for increased toxic effects of the chemicals used, and for the overall push for more natural products in the food industry, the food industry has been looking for more natural alternative for safe processing and storage of chicken meat.

Enter: Wine Industry Residues

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After the grapes are harvested and crushed to collect the juice for wine, there still remains squished up grapes (residue/pomace) that can be used for other products, such as grappa, animal feed, or fertilizer.  The seeds and skins of the crushed grapes, which make up about 30% of the total volume of the grapes used in wine production, are very rich in phenolic compounds, which have high antioxidant characteristics.  It is because of this high antioxidant quality that has drawn food industry scientists toward these crushed grape skins and seeds as a natural mechanism for preserving and storing chicken meat for consumption.

The overall purpose of this study was to examine whether or not crushed grapes, or grape crush by-products, would be suitable as natural antioxidants for keeping chicken meat consumable after processing and storing.

Methods

The grapes used in this study were two native North American varieties of species Vitis labrusca, Isabel and Niagara, and were supplied by a local winery in Brazil.  Chicken meat was provided by a local slaughterhouse, which underwent the standard procedures for preparation. 

Grape crush residues were prepared into grape extracts for functioning as a preservative by undergoing drying, grinding, and processing, using standard laboratory procedures (let me know if you need details and I’m happy to supply them). 

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Five treatments were administered in this study: 1) Isabel Grape Extract; 2) Niagara Grape Extract; 3) Butylated hydroxyoluene (a synthetic preservative); 4) a synthetic commercial mixture of sodium erythorbate, citric acid, and sugar; and 5) a control without any antioxidant preservatives.  Both raw and cooked samples were analyzed for thiobarbituric acid reactive substances (a.k.a. “nasty toxic chemicals”), pH, color, and sensory attributes (smell, taste, color).

Results

Phenolics/Antioxidants

  •       The Isabel grape variety had higher phenolics (antioxidants) than the Niagara grape residue.
  •       Both grape varieties had higher phenolics (antioxidants) than all other fruit residues.
  •       Total phenolic levels are influenced by multiple factors, including ripeness/maturity of the grape at harvest, grape variety, harvest practices, geographic origin, conditions at harvest and during storage, etc.

“Nasty Toxic Chemicals”

  •       The control (no antioxidant preservative added) had the highest level of these nasty chemicals.  In cooked samples, the values of nasty chemicals in the control were still too high for safe consumption.
  •       There were no significant differences in the levels of these nasty chemicals between either of the grape residues and the synthetic antioxidants in raw samples, meaning that the grape residues were just as effective as a preservative as the synthetics.
  •       After cooking, the grape residues are more effective than the synthetic residues, since the action of cooking induces increased oxidation (which is combated by the higher antioxidant levels in the grape residues).

pH

  •       The pH of the grape or synthetic extracts did not change the pH of the chicken meat.

Sensory characteristics

  •       The grape extracts/natural antioxidants did change the color of the chicken meat when compared to the synthetic antioxidants.  This is likely due to the fact that the grape extracts were darker purple, due to the nature of the grape color itself at the start of the process.
  •       Most treatments did not differ in flavor, though the Niagara treatment did show a different flavor than the rest (a grape/wine flavor).
  •       In regards to odor, the control and the Niagara treatments showed differed odors than the other treatments.  The control likely had been too oxidized and thus unfit for consumption, and the Niagara showed some grape/wine characteristics in the smell (as with the flavor as well).

What does this all mean?

It is clear from the results of this study that grape extract made from the leftover crushed grapes after harvest would be effective natural antioxidants for use as a chicken meat preservative, and would be just as effective as those synthetic products already on the market.

By using two grape varieties, the study was able to show that there are significant differences between grape varieties in regards to the sensory characteristic changes made on the chicken meat by using grape extract (color, flavor, odor changes), and how it will matter which grape variety is used when creating such a natural antioxidant/preservative.  As shown in this study, the Isabel grape variety would be much more suitable, as it is just as effective an antioxidant as the synthetic products, and it does not alter the color/flavor/odor of the chicken meat.  The Niagara variety, on the other hand, was just as effective as an antioxidant, however, it changed the color/flavor/odor of the chicken meat and introduced a “hint of wine”, which would likely cause a decrease in chicken meat sales (and would look, frankly, sketchy).

I think this is a great way to use the leftover crushed grapes after the harvest, and introduces a new natural product for preserving chicken meat, and who knows, maybe could increase other health benefits associated with grapes and wine.

I wonder…would resveratrol levels be increased in chicken meat treated with the antioxidant grape extract preservatives?? Hmmm…that’d be a great study!

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I’d love to hear from you!  Feel free to comment below about what you’ve read today!

Full citation of the article discusses today: 

Selani, M.M., Contreras-Castillo, C.J., Shirahigue, L.D., Gallo, C.R., Plata-Oviedo, M., and Montes-Villanueva, N.D. 2011. Wine industry residues extracts as natural antioxidants in raw and cooked chicken meat during frozen storage. Meat Science 88: 397-403.
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!

3 comments for “Grape Residues or Pomace as a Meat Preservative?

  1. Gregory
    September 15, 2012 at 9:57 am

    I am thinking of starting a business making chicken jerky treats for dogs and am looking into natural preservatives to use on the chicken to extend their shelf life. I’d be very interested in knowing how the Grape Residue is processed in order be used on the meat.
    Thanks,

    • Becca
      September 15, 2012 at 9:57 am

      Hi Gregory,

      For this type of question, I highly recommend emailing the author of the study directly to get specific details on how they processed the residues. C.J. Contreras-Castillo was the primary corresponding author on that paper, and the email for that author is ccastill@esalq.usp.br

      Best of luck!

  2. lenny_rean
    November 2, 2012 at 4:38 am

    Awesome! This is great for preserving chicken meat. I just read this idea and I am amazed.

Comments are closed.