Changes of DNA quality and meat physicochemical properties in bovine supraspinatus muscle during microwave heating.

BACKGROUND: The responses of foods to microwave exposure are usually evaluated only in terms of physicochemical properties, thus undervaluing the importance of DNA in an authentication process by methods based on polymerase chain reaction (PCR). In this study, the time effect of microwave heating on some meat physicochemical properties and DNA quality has been investigated. RESULTS: Cooking loss, instrumental colour, pH and other physicochemical parameters varied significantly during microwave cooking, reaching the lowest/highest values after 2.5 min of cooking. The exposure of meat to microwaves was found to affect characteristically the quality of extracted DNA (i.e. yield, purity and degradation). PCR products of both mitochondrial and nuclear regions were successfully observed in all samples. However, the band for large fragments became progressively fainter as treatment time increased. CONCLUSIONS: Microwave heating caused physicochemical changes in bovine supraspinatus muscle and influenced characteristically the yield and integrity of the extracted DNA, indicating that an accurate DNA quantification and a rational choice of the genes (i.e. mtDNA versus nDNA, fragment size, etc.) to be amplified are fundamental in an authentication process by PCR-based methods.

Appearance, consumer liking and preferences of Lucanian 'Soppressata' salami.

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.

Creating Public Awareness of How Goats Are Reared and Milk Produced May Affect Consumer Acceptability.

This study evaluated whether showing a video of the different ways of raising goats for milk affected consumer acceptability. Four combinations, 2 Videos (intensive [INT] and semiextensive [SEM] system) × 2 Milk Types (semiskimmed [S] and whole [W] milk), were evaluated by 70 habitual consumers of goat milk, who scored their liking and purchase intention during blind (B), expected (E), and informed (I) acceptability sessions. In the B session, consumers tasted both milk types without information. S samples were preferred over W samples. In the E session, SEM video created high expectations in terms of milk liking and purchase intent, whereas the opposite happened when showing INT video. In the I session, consumers showed a clear preference for combinations created using SEM video, regardless of milk type. W-SEM and S-INT were worse (negative disconfirmation) and better (positive disconfirmation) than expected, respectively. A complete assimilation toward expectations occurred only for S-INT. INT video adversely affected the acceptability of S samples. Concerning purchase intent, W-SEM and S-SEM were worse than expected, but the assimilation was complete only for S-SEM: SEM video increased purchase intent for S samples.

The role of cognitive styles and sociodemographic characteristics in consumer perceptions and attitudes toward nonhuman animal welfare.

Given the increasing importance of exploring consumers' concerns about the welfare of farmed animals, a survey questionnaire was designed to investigate the role of cognitive styles along with sociodemographic characteristics in consumers' perceptions about nonhuman animal welfare (AW) and their willingness to pay for animal-friendly products. The results revealed that the survey respondents were concerned about AW and had negative perceptions of the way animals were treated. They showed positive attitudes toward some actions to be taken for improving AW and strongly agreed to pay more for animal-friendly products. Consistent with previous studies, results revealed significant associations between sociodemographics and concern toward AW. However, some observed differences were highlighted by cognitive styles rather than by sociodemographic characteristics. These results indicate a significant link between cognitive styles and perceptions and attitudes toward AW, which may outweigh previously found sociodemographic differences and fuel the contemporary debate on AW.

Image analysis with the computer vision system and the consumer test in evaluating the appearance of Lucanian dry sausage.

The object of the investigation was the Lucanian dry sausage appearance, meant as color and visible fat ratio. The study was carried out on dry sausages produced in 10 different salami factories and seasoned for 18 days on average. We studied the effect of the raw material origin (5 producers used meat bought from the market and other 5 producers used meat from pigs bred in their farms) and of the salami factories or brands on meat color, fat color and visible fat ratio in dry sausages. The sausages slices were photographed and the images were analysed with the computer vision system to measure the changes in the colorimetric characteristics L*, a*, b*, hue and chroma and in the visible fat area ratio. The last parameter was assessed on the slice surface using image binarization. A consumer test was conducted to determine the relationship between the perception of visible fat on the sausage slice surface and acceptability and preference of this product. The consumers were asked to look carefully at the 6 sausages slices in a photo, minding the presence of fat, and to identify (a) the slices they considered unacceptable for consumption and (b) the slice they preferred. The results show that the color of the sausage lean part varies in relation to the raw material employed and to the producer or brand (P<0.001). Besides, the sausage meat color is not uniform in some salami factories (P<0.05-0.001). In all salami factories the sausages show a high uniformity in fat color. The visible fat ratio of the sausages slices is higher (P<0.001) in the product from salami factories without pig-breeding farm. The fat percentage is highly variable (P<0.001) among the sausages of each salami factory. On the whole, the product the consumers consider acceptable and is inclined to eat has a low fat percentage (P<0.001). Our consumers (about 70%) prefer slices which are leaner (P<0.001). Women, in particular, show a higher preference for the leanest (P<0.001).

Measurement of meat color using a computer vision system.

The limits of the colorimeter and a technique of image analysis in evaluating the color of beef, pork, and chicken were investigated. The Minolta CR-400 colorimeter and a computer vision system (CVS) were employed to measure colorimetric characteristics. To evaluate the chromatic fidelity of the image of the sample displayed on the monitor, a similarity test was carried out using a trained panel. The panelists found the digital images of the samples visualized on the monitor very similar to the actual ones (P<0.001). During the first similarity test the panelists observed at the same time both the actual meat sample and the sample image on the monitor in order to evaluate the similarity between them (test A). Moreover, the panelists were asked to evaluate the similarity between two colors, both generated by the software Adobe Photoshop CS3 one using the L, a and b values read by the colorimeter and the other obtained using the CVS (test B); which of the two colors was more similar to the sample visualized on the monitor was also assessed (test C). The panelists found the digital images very similar to the actual samples (P<0.001). As to the similarity (test B) between the CVS- and colorimeter-based colors the panelists found significant differences between them (P<0.001). Test C showed that the color of the sample on the monitor was more similar to the CVS generated color than to the colorimeter generated color. The differences between the values of the L, a, b, hue angle and chroma obtained with the CVS and the colorimeter were statistically significant (P<0.05-0.001). These results showed that the colorimeter did not generate coordinates corresponding to the true color of meat. Instead, the CVS method seemed to give valid measurements that reproduced a color very similar to the real one.