Tea polyphenol (TP), apple polyphenol (AP), and cinnamon polyphenol (CP) are all enriched with antioxidant components, present enormous potential as natural antioxidants in meat products. The objective of this study was to evaluate the physicochemical properties, residual nitrites, and formation of N-nitrosamine (NA) in dry-fried bacons with three aforementioned plant polyphenols and ascorbic acid (AA). The results show that both plant polyphenols and AA significantly reduced pH, lipid oxidation and residual nitrite content when compared to the control (P < 0.05). Only AP exhibited a protective effect against protein oxidation-induced damage in bacon, and N-nitroso-methyl phenylamine (NMPhA) contents were significantly affected by plant polyphenols (P < 0.05). Bacon containing 300 mg/kg AP produced less thiobarbituric acid reactive substance (TBARS) (0.59 MDA/kg), carbonyl contents (2.30 nmol/mg protein) and NMPhA formation (1.211 ng/kg). In conclusion, plant polyphenols, particularly AP, have the potential to be used as natural antioxidants for reducing oxidation and nitrite application level while also improving the safety of bacon.

The effects of different nitrite levels (50, 100, and 150 mg/kg meat) and dry-frying temperatures (100, 150, 200 and 250 °C) on the moisture movement, colour, sensory variables and residual nitrite and N-nitrosamine levels in smoked bacon were investigated. Increasing the dry-frying temperatures significantly increased the cooking loss and decreased the moisture content (P < 0.05). The bacon L*-values showed an increasing trend at first and then decreased, with the highest value of the bacon with 150 mg/kg nitrite was obtained at 100 °C and 150 °C. In addition, a*-values were significantly affected by the nitrite level and dry-frying temperature (P < 0.05), with the highest value of the bacon samples with 100 and 150 mg/kg nitrite observed at 250 °C. The residual nitrite content level initially increased (from unheated control to 150 °C) and then decreased (from 150 to 250 °C) sharply with increasing dry-frying temperatures in the bacon samples with the same sodium nitrite levels. N-methyl-N-nitrosoaniline (NMPhA) and N-nitrosomorpholine (NMOR) were measured in a number of smoked bacon samples, and a significant positive correlation (R2 = 0.772) was found for N-nitrosamines (NA) contents and nitrite levels (P < 0.05). The maximum levels of NMPhA and NMOR were detected when the bacon with 150 mg/kg sodium nitrite was pan-fried at 200 °C and 150 °C, respectively.

A large amount of zinc protoporphyrin IX (ZnPP) is found in nitrite/nitrate-free dry-cured meat products, such as Parma ham, and is known to contribute to the favorable bright red color of the latter. ZnPP is a metalloporphyrin, in which zinc is coordinated, instead of iron, in the porphyrin ring. ZnPP proved to be more stable than heme, and its formation should be favored in dried meat products to improve color without the addition of nitrites or nitrates. Toward that, understanding the mechanisms of formation of ZnPP in nitrite/nitrate-free dry-cured ham would be important. In this lecture, I introduce some of our research group's findings regarding the endogenous and exogenous factors contributing to the formation and distribution of ZnPP in Parma ham and why ZnPP formation is suppressed in common cured meat products.

Zinc protoporphyrin IX (ZnPP) mainly contributes to the red color of dry cured ham without nitrites/nitrates. Here, we examined the effects of acids used for pH adjustment, pH, and microorganisms on ZnPP formation. The results showed that ZnPP formation and optimal pH were dependent upon the acid type. In the presence of microorganisms, the optimal pH for ZnPP formation shifted to higher values, with the amount of formed ZnPP markedly increased at the shifted optimal pH. Additionally, two bacterial strains isolated from incubated pork homogenate exhibited an enhanced ability to form ZnPP. Although the two isolated bacteria are not edible, inoculation with one bacterium into minced meat resulted in formation of large amounts of ZnPP and color closer to that of nitrite-added meat. These results suggest that appropriate food-grade bacterial strains can improve the color of various fermented meat products in the absence of nitrites/nitrates.

In recent decades, processed meat consumers have drastically revised their consumption patterns and have gained an increasing awareness of related health concerns. Although several studies have examined the role of meat products in the human diet, we observed a certain scarcity in the multi-perspective approach to the health implications of cocked ham. Therefore, we decided to verify different sources of potentially unhealthy constituents by simultaneously analysing the role that saturated fats, salt and nitrites play in consumer perception. The purpose of this paper was to investigate consumer preferences for healthier processed meat, in particular the specific objective of this study was to evaluate the balance between intrinsic and extrinsic characteristics and the components or additives that could pose a risk to the health of consumers, by considering the sensory and marketing characteristics involved in the choice of cooked ham. With these aims, two different analyses on stated preferences were carried out: firstly, a principal component analysis was performed to identify the main consumer attitudes towards meat products; subsequently, a conjoint analysis was carried out in order to identify the descriptive attributes. The results show that the presence of high salt content and nitrites discourage the intention to purchase, as the presence of a high fat content also does, however at the same time, consumers attach importance to taste, colour and juiciness that are strongly influenced by the above mentioned potentially unhealthy compounds. The overall results are strongly consistent with previous studies but evidence a certain dichotomy between sensory properties and health attributes.

We assessed the effect of the raw material origin and preservative on the appearance and consumer liking of Soppressata salami to give information concerning the best process conditions to fulfil consumer needs. The effect of visible fat ratio on consumers' acceptability and preference was also evaluated. Image analysis based on Computer Vision System showed that Soppressata cured with nitrites had higher levels of red, yellow, hue and chroma, whereas its fat showed higher levels of lightness, redness, and lower levels of hue. Consumers liked more cured Soppressata, made by using pork cuts and fat from pigs bred on plants using growth-to-finish systems and transformed on site as compared with products obtained by using raw material bought from the market. Most of the consumers considered acceptable the slices with lower visible fat ratio (8.28-17.98%). Therefore, a visible fat ratio below 18%, the use of internal meats and added nitrates appear to be the best process conditions to fulfil consumer needs.