Olive polyphenols (OPP) as a substitute of nitrite in ham

Abstract

Cooked ham is a particularly popular cured meat product. Nonetheless, meat consumption constitutes a controversial issue, as researchers correlate red and cured meat with the development of colorectal cancer. One of the main compounds of the cured cooked ham is nitrite. Although, its residual amount in products is considered as responsible for the formation of N-nitrosamines and the provocation of cancer. Due to their antimicrobial and antioxidant properties, olive polyphenols (OPP) may substitute a part of nitrite in cooked ham. In addition, there might be a possible reaction with nitrite and OPP that could subsequently reduce the residual amount in the product. The purpose of this project was the production of cooked hams on a laboratory scale and the investigation of the possible use of OPP, to partly substitute the used nitrite. Varying OPP (0, 50 , 150 and 1000 ppm) and nitrite (0, 50, 150 ppm) concentrations were used. Following the assumption that by adding OPP to the same amount as nitrite, and supposing OPP taking care of the rest nitrite, the nitrosamines should be reduced. The extra OPP of 1000 ppm was the check if antimicrobial effect exists. The main examination was concerning the influence of the oxidation process, the microbial load, the amount of residual nitrite and the colour development on the produced hams. The results revealed that OPP at 1000 ppm did not show any inhibitory effect against the total aerobic counts and yeast and mold counts. As it was shown the decrement of microbial growth was favored by higher nitrite concentrations, before and after incubation at ambient temperature for 48 h. Nonetheless, the results were not significant (p > 0.05). Bacteria of the total aerobic counts were also isolated, showing that in most of the cases the same bacteria (Leclercia adecarboxylata (T); GQ856082 in the samples with 150 ppm nitrite and 150 ppm OPP, Staphylococcus warneri (T); L37603 in the samples without added nitrite and OPP) were identified in the samples of the same concentrations. Furthermore, OPP in the used concentrations did not show a significant (p > 0.05) antioxidant capacity in TBAR values, in contrast to nitrite (p < 0.05). After the influence of nitrite and OPP was assessed, with regard to all the colour parameters after cooking of the ham, it was revealed that nitrite had a significant (p < 0.05) effect on increasing the redness and yellowness of the hams, whereas OPP did not seem to have any significant (p > 0.05) contribution. Finally, not unexpectedly, there was a significant (p < 0.05) increase in residual nitrite by increasing the nitrite concentration. At the same time, the OPP influence was not significant ( p > 0.05), but it was revealed a downward trend after 150 ppm. This study indicates that nitrite is a particularly powerful additive, and its substitution requires further research.

Popular Abstract

Cooked ham is a particularly popular cured meat product. When meat undergoes curing, it is injected by small needles with a specific amount of salt solution containing different ingredients and additives. The name of the main chemical compound of this solution is nitrite, and it is an additive responsible for the distinctive features of the ham, such as its special colour and flavour. At the same time, it has additional effects as it is a drastic antimicrobial mainly against the life-threatening, lethal toxin producing microorganism Clostridium botulinum, but also as it prevents the degradation of lipids from oxygen, a complicated process that causes the organoleptic deterioration of the product. However, cured and red meat consumption constitutes a controversial issue, as researchers correlate it with the development of cancer. This effect is attributed to a small amount of nitrite that remains in the product after the manufacturing process, called residual or rest nitrite, and is considered responsible for the subsequent formation of carcinogenic compounds, known as N-nitrosamines. Due to their antimicrobial and antioxidant properties, olive polyphenols may substitute a part of nitrite in cooked ham. In addition, there might be a possible reaction with nitrite and olive polyphenols that could additionally reduce its residual amount in the product.The purpose of this project was the production of cooked hams on a laboratory scale and the investigation of the possible use of olive polyphenols, to partly substitute the used nitrite. Different concentrations of olive polyphenols and nitrite were used, following the assumption that by adding olive polyphenols to the same amount as nitrite, and supposing that they take care of the rest nitrite, the N-nitrosamines should be reduced. An extra amount of olive polyphenols was added, to investigate if an antimicrobial effect exists. The focus was given to the influence of olive polyphenols to the oxidation process, the growth of microorganisms, the amount of residual nitrite and the colour of the produced hams.The results revealed that even if olive polyphenols were used in their higher amount they did not have any inhibitory effect against the different microorganisms in the different cooked hams. On the other hand, nitrite seemed to be the responsible component for their decrement, in its higher added amount. However, the results were not as so called “significant” in statistical terms, meaning that it cannot be guaranteed that they were not a matter of chance. In addition, some of the microorganisms that were detected in the produced cooked hams with the higher amount of nitrite were identified.
The results showed that in most of the cases, bacteria of the group with the name Leclercia and the second name adecarboxylata (in order to be distinguished from the other members of this group), were in the samples with the higher amount of nitrite and equal amount of olive polyphenols. Also bacteria with the name Staphylococcus and the second name warneri were the dominant in the samples without added nitrite and olive polyphenols.Furthermore, olive polyphenols in the used concentrations did not show to inhibit the lipid oxidation process, in contrast to nitrite that had a statistically significant influence. With regard to the other important parameter, the colour, it was revealed that nitrite contributed to a more intense pigmentation (characteristic colour of the cooked ham) when olive polyphenols did not seem to contribute (not statistically significant results). Finally, and not unexpectedly, there was a higher amount of rest nitrite in the produced cooked hams with higher amount of added nitrite, but again, olive polyphenols influence cannot be determined effective.
This research shows that nitrite is a principally potent additive, and its substitution involves further research.

• author: Tzima, Aikaterini
• supervisor: Eva Tornberg
• organization: Food Technology and Nutrition (M.Sc.)
• course: KLTM01 20161
• year: 2016
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: antioxidant, antimicrobial, residual nitrite, Nitrite, OPP, colour, food engineering, livsmedelsteknik
• language: English
• id: 8885189
• date added to LUP: 2016-08-01 11:18:03
• date last changed: 2016-08-01 11:18:03