Visible and near-infrared spectral imaging combined with robust regression for predicting firmness, fatness, and compositional properties of fresh pork bellies.

Belly is a widely consumed pork product with very variable properties. Meat industry needs real-time quality assessment for maintaining superior pork quality throughout the production. This study explores the potential of using visible and near-infrared (VNIR,386-1015 nm) spectral imaging for predicting firmness, fatness and chemical compositional properties in pork belly samples, offering robust spectral calibrations. A total of 182 samples with wide variations in firmness and compositional properties were analysed using common laboratory analyses, whereas spectral images were acquired with a VNIR spectral imaging system. Exploratory analysis of the studied properties was performed, followed by a robust regression approach called iterative reweighted partial least-squares regression to model and predict these belly properties. The models were also used to generate spatial maps of predicted chemical compositional properties. Chemical properties such as fat, dry matter, protein, ashes, iodine value, along with firmness measures as flop distance and angle, were predicted with excellent, very good and fair models, with a ratio prediction of standard deviation (RPD) of 4.93, 3.91, 2.58, 2.54, 2.41, 2.53 and 2.51 respectively. The methodology developed in this study showed that a short wavelength spectral imaging system can yield promising results, being a potential benefit for the pork industry in automating the analysis of fresh pork belly samples. VNIR spectral imaging emerges as a non-destructive method for pork belly characterization, guiding process optimization and marketing strategies. Moreover, future research can explore advanced data analytics approaches such as deep learning to facilitate the integration of spectral and spatial information in joint modelling.

Pork quality and histological properties of longissimus muscle from boars and early and late immunocastrated pigs.

Immunocastration has been introduced in pig production to reduce boar taint. However, there is not much information on how different schedule of immunocastration affects meat quality, especially muscle histological properties. In this study, carcass and meat quality characteristics, histological properties of the longissimus dorsi muscle, sensory characteristics and fatty acid composition of meat and fat from entire males (EM), late immunocastrated (LIC, first dose 8 weeks before slaughter, second dose 4 weeks before slaughter) and early immunocastrated pigs (EIC, first dose 13 weeks before slaughter, second dose 8 weeks before slaughter) were compared. Fat thickness was greater in EIC than in LIC and EM. Meat quality parameters differed mainly between EIC and EM, as EIC had a higher pH 45, lower electrical conductivity, lighter and more yellowish loins and lower drip loss than EM. EM had a higher protein and moisture content and a lower fat content than EIC and LIC. No major effect on histological properties was observed, however, the percentage of fast-twitch oxidative fibres tended to be lower in both LIC and EIC animals compared to EM. Pork from EM had higher boar taint and lower pork odour and flavour scores and higher pig and boar taint flavour scores. The results of this study show that the immunocastration schedule influences some carcass, meat and fat quality traits and, because of that, it can be modified to obtain the desired final product.

The role of carcass processing (hot vs. cold boning) on pork belly morphological and mechanical characteristics.

This study assessed the effect of boning processing method (hot vs. cold) on pork belly morphological and mechanical traits and the evolution of these traits during refrigerated storage postmortem (PM). A total of 14 crossbred pigs were slaughtered and their carcasses and bellies processed under two conditions: hot boning (n = 14, right sides of carcasses cut immediately after slaughter) and cold boning (n = 14, left sides of carcasses cut 24 h PM). Morphological and mechanical evaluations were made at 1-, 5-, 24- and 48-h PM on the hot-boned bellies, and at 24 and 48 h on the cold-boned ones. Compared to the cold-boned bellies, the hot-boned ones were shorter, wider and thicker (P < 0.01), with greater firmness (flop distance and angle) (P < 0.001) and cohesiveness (skin-fat separation) (P < 0.05 in the dorsal and central sections). At 48 h PM, hot-boned bellies had a thicker skin (P < 0.001) and softer subcutaneous fat in the dorsal-cranial and central sections (finger scores and compression textural test) (P < 0.05). Morphological and mechanical traits for hot-boned bellies confirmed an intense shortening and hardening (increased firmness and cohesiveness), and a slight yield loss from 1 to 24 h PM. From 24 to 48 h PM, there was a certain flattening in hot-boned bellies that was associated with a slight softening (reduced firmness). Although a larger sample may be needed to corroborate these findings, they demonstrate the impact of carcass processing method and refrigerated storage time on belly quality. This may be useful for the pork industry for obtaining the desired type of belly.

The effect of immunocastration of male and female Duroc pigs on the morphological, mechanical and compositional characteristics of pork belly.

Pork belly is an important and heterogeneous cut, characterized by its fat content. Immunocastration is an alternative to surgical castration that can modify the composition of carcasses and cuts and it can affect at its processing. This work compares the morphological, mechanical and compositional characteristics of pork belly of (1) pure Duroc pigs from surgically castrated males (CM), entire females (EF) and immunocastrated females (IF), and (2) Duroc crossbreed pigs from immunocastrated males (IM) and entire males (EM). Two trials were carried out: Trial 1, in which 36 bellies were evaluated, 12 from each sexual type, CM, EF and IF; and Trial 2, where 30 bellies were used, 15 from each sexual type, IM and EM. Results show few differences in bellies from EF and IF, while those from CM were fatter and firmer and with lower polyunsaturated fat. Bellies from IM were longer and firmer than those from EM, and their skin was thinner. IM bellies had higher saturated and lower polyunsaturated fat than those from EM. To conclude, the sex of the pigs affects belly characteristics and this could be a criterion for determining the destination of the bellies in the cutting plant. Immunocastration of pure Duroc females had a lower effect on the belly characteristics when compared to those from entire females, but some differences could be found in the fat distribution. Immunocastration of Duroc crossbred males produces firmer and thicker bellies, with a thinner skin, that could be advantageous for slicing and further processing.

Productive performance and in vivo body composition across the growing and finishing period and carcass traits in pigs of four sex types.

This study compares performance, body and carcass composition among castrated (CM), immunocastrated (IM) and entire males (EM), and females (FE) at 30, 70, 100 and 120 kg of body weight (total of n = 92; 20-24/sex type). Overall, IM had similar growth and feed intake to CM and greater than EM and FE. At each slaughter stage, IM had a lower killing-out percentage than CM and FE, in line with their heavier liver and kidneys. Flare fat proportion and backfat thickness on the ham and at the last rib level were similar for IM, EM and FE, and these were lower than CM. In EM and FE, backfat between the 3rd and 4th last ribs was lower and carcass lean content was higher than in CM, whereas IM were intermediate and not different to the other sexes. Females showed the largest ham proportion, this cut being leaner and less fatty than in CM. Belly proportion was higher in CM than in EM.

Understanding consumers' perceptions towards Iberian pig production and animal welfare.

The Spanish market offers a greater variety of Iberian pork products. The aim of this paper is to determine the perception of consumers of several aspects of Iberian pig production and animal welfare depending on the consumers' characteristics. Consumers from two Spanish regions (n = 403) answered a questionnaire about their beliefs and the importance of pig production, their purchase intentions and their willingness to pay. Consumers were segmented according to their level of knowledge about Iberian pig production. The results of this work indicate that consumers have poor knowledge about Iberian pig production. Even so, consumers show a remarkable preference for Iberian products, especially when the animals are reared freely and in natural conditions, giving great importance to animal welfare. Consumer preferences indicate the importance of emphasizing Iberian traditional pig product characteristics on the label to promote their purchase choices.