Zinc Protoporphyrin-Rich Pork Liver Homogenates as Coloring Ingredients in Nitrite-Free Liver Pâtés.

This study aimed to investigate the coloring ingredient potential of liver homogenates that form Zn protoporphyrin (ZnPP), a natural red pigment, after anaerobic incubation. Liver homogenates were used to develop nitrite-free sterile pork liver pâtés. These homogenates were applied in the formulation of pâtés directly or after centrifugation to obtain a pellet that was highly concentrated in ZnPP. Both the whole homogenate and its insoluble fraction were adjusted to pH 7.5 before their use in the formulation of pâtés with and without antioxidant (0.5% ascorbate plus 0.1% tocopherol) addition. Pâtés formulated with the whole homogenate showed color and texture characteristics that were similar to those of the positive control with nitrite. However, high levels of the insoluble fraction also led to pâtés with improved color characteristics but with a two-fold softened texture. Therefore, the form and amount of ZnPP added played roles in the final appearance of the product. The ZnPP pigment was more stable than heme in the sterilization treatment, and antioxidant addition proved to be unnecessary. The ZnPP-rich ingredients allowed for the preparation of nitrite-free cooked liver pâtés with a stable red color and could thus be potentially applied in other uncured cooked meat products.

Utilization of Porcine Livers through the Formation of Zn-Protoporphyrin Pigment Optimized by a Response Surface Methodology.

There is a growing demand for clean-label products. This study aimed to obtain a food-grade coloring ingredient for meat products based on the formation of Zn-protoporphyrin from porcine livers, thus contributing to the development of nitrite-free products. First, the effects of sodium disulfite and acetic, ascorbic, and lactic acids on the formation of Zn-protoporphyrin and the total microbial count were studied. The combination of ascorbic and acetic acids resulted in a higher Zn-protoporphyrin content than acetic acid alone, and microbial levels were maintained (ca. 3 log CFU/mL). Second, a response surface methodology was used to maximize Zn-protoporphyrin while maintaining microbiological food standards. To that end, the effects of pH (4.2-5.4), incubation time (3-30 h), and temperature (25-50 °C) were studied. The selected conditions for Zn-protoporphyrin formation involved anaerobic incubation at pH 4.8 and 45 °C for 24 h. The safety was validated through challenge testing for relevant pathogens (Listeria monocytogenes, Salmonella spp., and Clostridium perfringens). A significant reduction (>6 log units) was observed in the selected conditions for L. monocytogenes and Salmonella, whereas C. perfringens spores remained at the inoculated levels. The optimized procedure is proven to be microbiologically safe, and may improve the color of nitrite-free meat products.

Co-Creation with Consumers for Packaging Design Validated through Implicit and Explicit Methods: Exploratory Effect of Visual and Textual Attributes.

Packaging is no longer a mere structural element that only aims to preserve foods, but it is also a powerful marketing tool able to affect product perception, purchase decision and consumers' food choices. Incorporating consumers' voices into packaging design through co-creation could maximise its impact on the market. The main goal of this exploratory study was to test the usefulness of co-creation with consumers for packaging design. For that purpose, a survey with 200 Spanish participants was conducted to find out which of the presented visual and textual packaging attributes were the most appropriate. A validation study with 40 participants using implicit (eye tracker, galvanic skin response and automatic facial expression analysis) and explicit measurements was used to test the packaging co-created by consumers against some of its possible competitors in the market. The co-creation process with consumers allowed for the identification of the visual and textual attributes, among the available options, that best fit their preferences, whereas the validation process confirmed that the packaging design co-created by consumers was equally or even preferred over the competitors. The information gathered might help designers and marketers to guide the packaging design for fish products in the Spanish market.

Formation of Zn-protoporphyrin during the elaboration process of non-nitrified serrano dry-cured hams and its relationship with lipolysis.

This study assessed the ZnPP content, heme content, salt content, and instrumental color in the biceps femoris and semimembranosus muscles during the elaboration of Serrano dry-cured ham manufactured without the addition of nitrate and nitrite for 15 months. The effects of lipolysis and lipid oxidation on the content of Zn-protoporphyrin were also investigated in the biceps femoris. We found that the maximum formation of Zn-protoporphyrin occurred between end of resting and 6 months of processing, which coincides with temperature increase during processing and the end of salt equalization. Zn-protoporphyrin further increased in the biceps femoris until 9 months of processing but remained unchanged in the semimembranosus. Free fatty acid content increased till 6 months and then remained unchanged until the end of the process. These findings and those from an in vitro study reinforced the idea that the release of free fatty acids can promote the activity of the endogenous enzyme ferrochelatase and contribute to the formation of Zn-protoporphyrin from heme. However, the content of Zn-protoporphyrin decreased at the end of the processing, which may be due to the progression of lipid oxidation.

Consumer Attitudes toward Consumption of Meat Products Containing Offal and Offal Extracts.

The development of food products containing offal and offal extracts could be part of the solution to the upcoming demand for animal protein. This study aimed to determine Spanish consumers' attitudes toward offal and the development of meat products containing offal extracts. Consumers' perceptions were evaluated by means of focus group discussions and a survey (N = 400) to validate the focus group results in various Spanish provinces. The theory of planned behavior was used to examine consumer attitudes. Results indicated that nutritional properties, environmental sustainability, and affordability were the main drivers, while sensory attributes, low frequency consumption, and perceived higher content of undesirable compounds were the main barriers. Three segments were identified according to their beliefs: those in favor of these products, those that were health and environmentally conscious, and those who were reluctant about them. The identification of these segments and their profiles demonstrated the necessity to focus efforts on providing reliable information on sensory and health-related issues to improve acceptability. Attitude was the most important predictor of behavioral intention regarding the global model, while the social component (subjective norm) was significant for two of the identified segments, emphasizing the relevance of the social component for acceptability.

Effects of post mortem pH and salting time on Zinc-protoporphyrin content in nitrite-free Serrano dry-cured hams.

There is a growing demand for clean label products and thus the elimination of curing additives in various dry-cured meats is of interest while maintaining colour characteristics. This study was aimed to examine the effect of pH at 24 h post mortem (pHSM24h ≤ 5.4; 5.4 > pHSM24h < 5.9; pHSM24h ≥ 5.9) and salting time (standard vs reduced) on zinc-protoporphyrin content, heme content and other physicochemical parameters of Serrano dry-cured hams manufactured without the addition of curing agents. Results showed that in those hams with higher post mortem pH heme content was increased whereas ZnPP content and proteolysis index were decreased. Reduced salting time decreased salt content whereas ZnPP and heme contents remained unaffected. Lower post mortem pH and reduced salting time led to a higher content in various free fatty acids which, in turn, were found to correlate positively with ZnPP formation. However, the observed changes in heme and ZnPP contents had no effect on the instrumental color of the final product.

Effect of high hydrostatic pressure on the oxidation of washed muscle with added chicken hemoglobin.

The role of chicken hemoglobin in lipid oxidation of washed chicken muscle exposed to high hydrostatic pressure (0, 200, 400 and 600 MPa) was examined. The observed decrease in redness was higher with elevated pressures (5.0 vs 3.7). During storage, redness decreased in samples exposed to 400 and 600 MPa. This decrease was concomitant with the progression of oxidation and the 2.5 fold decrease of soluble heme. An additional experiment was conducted to examine the effect of the hemoglobin mode of addition into pressurized muscle. The exposure at 600 MPa led to washed muscle oxidation even in the absence of hemoglobin, thus indicating that pressure treatments triggered lipid oxidation. However, the presence of native or pressurized hemoglobin into pressurized washed muscle caused more hexanal than the pressurized control without hemoglobin. Overall, results suggest that membrane disruption and the release of hemin are crucial for the onset of oxidation.

Zinc-protoporphyrin content in commercial Parma hams is affected by proteolysis index and marbling.

The contents of zinc-protoporphyrin (ZnPP) and heme in twenty-four sliced Parma hams made without the addition of curing agents were determined. Expressed on a dry weight basis, ZnPP averaged 45 mg/kg and ranged from 23 to 85 mg/kg. The heme content averaged 37 mg/kg on a dry matter basis and ranged from 17 to 73 mg/kg. A Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression analyses were carried out to examine the existing correlations between these pigments and various physicochemical parameters in the final product. PCA showed the existence of associations between ZnPP, sensory redness and salt content. PLS suggests that the conversion of ZnPP from heme is facilitated in those hams with a higher proteolysis index and higher marbling.