Re-Veal the Beef Industry: Strategies to Produce High- Quality Beef From Young Cattle in Pastoral Systems

Key nutritional composition

Fat, protein, and collagen. Veal is lean meat and is considered as low-fat food for its lower than 3% fat content regardless of genetics, feeding systems, sex, and age/weight of calves at slaughter (Pestana et al., 2012; Domaradzki et al., 2017). On average, the intramuscular fat (IMF) content of veal longissimus muscle is about 1.95% across most studies. Fat content in meat products is of significant interest to both consumers and scientists due to its controversial role in human health where some lipids may be beneficial (e.g., n-3 fatty acids [FA]) while others are detrimental (e.g., saturated fats). On the other hand, fat plays a key role in flavor development and consumer acceptability and liking of meat. A low IMF content of meat is desired by certain consumers as they associate it with a healthier product (Testa et al., 2021). However, the IMF content of veal is below the minimum level of 3% suggested to be required to obtain acceptable palatability (Savell & Cross, 1988). The fat content of veal is mainly associated with on-farm factors (Tables 1–2), and generally, it is affected by animal age and sex, with higher fat levels observed in castrated animals (Marti et al., 2011, 2013), in females than males (Costa et al., 2006; Vavrišínová et al., 2021), and in older than younger calves (Monteiro et al., 2013; Yim & Hur, 2019; Araújo et al., 2020). Other factors such as animal feeding and genetics can also influence the fat content in veal, although the findings are inconsistent and depend on the muscles of interest. It is generally agreed that grazing or grass-fed calves result in leaner veal compared to those raised in feedlots with concentrates and other formulated diets (Miotello et al., 2009; dos Santos et al., 2013). Further, crossbreeding beef with dairy breeds has also been suggested to increase the IMF content of veal (Basiel & Felix, 2022).

Associated with its low IMF content, the FA composition of veal is characterized by a relatively high proportion of polyunsaturated fatty acids (PUFA). As a result, their proportions of saturated (SFA) and monounsaturated fatty acids (MUFA) tend to be slightly lower than in older animals. The high proportion of PUFA in veal meat is reflected in its relatively high PUFA/SFA ratio (∼0.3), which is known to have positive effects on consumers’ cardiovascular health (Chen & Liu, 2020). Although this ratio is still below the suggested minimum dietary level of 0.4, it doubles the ratio of older cattle (Wood et al., 2008). In terms of sensory quality, a higher IMF content in meat is more favorable due to its role in flavor development during cooking; however, the percentage of PUFA and PUFA/SFA ratio decrease with increasing levels of IMF (Scollan et al., 2006). Despite the favorable PUFA/SFA ratio of veal meat, its n-6/n-3 ratio is above the maximum of 4.0 suggested to reduce cardiovascular risk by its anti-inflammatory and anti-oxidative stress effects and by improving the endothelial function (Yang et al., 2016). The high n-6/n-3 ratio could be associated with the use of concentrates as the main component of the diet in most studies (Daley et al., 2010). Different studies (González et al., 2014; Gómez et al., 2015; Morittu et al., 2021) have demonstrated the effectiveness of the incorporation of linseed oil in the concentrate diet of veal to reduce its n-6/n-3 ratio. Such an effect would not be observed in pasture-fed cattle due to the low n-6/n-3 ratio in pasture feed (Pouzo et al., 2015), resulting in lower n-6/n-3 ratios (<4.0) in veal. Further, veal from Simmental calves was found to have higher levels of PUFA, PUFA/SFA, and n-6/n-3 ratios with less SFA and MUFA content compared to Holstein and the crossbred (Simmental × Holstein) (Kelava et al., 2009). The authors have also observed the lowest PUFA/SFA and n-6:n-3 ratios in Holstein and crossbred calves, respectively.

Veal is also an important source of dietary proteins contributing to a similar level of protein (20%–24%) to the meat from older animals. Collagen is a structural protein mainly deposited in connective tissues of the skeletal muscles which has been considered as an important component in maintaining acceptable tenderness and texture of meat. The total amount of collagen and the proportion of its soluble fraction are the key contributors to the variations in collagen-associated toughness. The amount of collagen increases while the solubility of collagen decreases with age, resulting in less tender meat (Monteiro et al., 2013). The collagen content of veal ranged from 0.6% to 1.8%, consisting of a 16.8% to 21.9% soluble fraction (Domaradzki et al., 2017). Genetic factors, growth rate, nutrition of animals, post-mortem processing (e.g., aging), and cooking could also alter the role of collagen in the textural properties of meat. For example, restricting the growth rate of yearling steers may result in tougher meat due to the lower percentage of soluble collagen (Fishell et al., 1985). The tenderization of meat during postmortem aging could be partially explained by the structural changes of collagen due to the proteolytic activities of collagenolytic cathepsins (Weston et al., 2002).

Cholesterol. Cholesterol is another component affecting the nutritional quality of meat due to the possible association with the increased risk of chronic diseases like cardiovascular disease (Berger et al., 2015). The concentration of cholesterol was lower in the skeletal muscle of Polish Holstein-Friesian calves compared to heifers, young bulls, and cows (Litwińczuk et al., 2015), suggesting that the age of cattle at slaughter may vary the cholesterol content. However, similar cholesterol levels were observed for veal (10 to 11 mo old) and young bulls (18 mo old) regardless of production systems (PGI or PDO specifications) (Monteiro et al., 2012). There was no effect of the sex of calves and slaughter seasons (autumn or spring) on cholesterol content observed in 3 muscles (biceps femoris, longissimus dorsi, and supraspinatus) of Barrosã-PDO veal 6–9 mo old (Costa et al., 2006). A significantly higher cholesterol content was observed in longissimus thoracis compared to longissimus lumborum and semitendinousus; however, the difference between other muscles was marginal (Mestre Prates et al., 2006). Similarly, no significant difference was observed between muscles (longissimus lumborum and semitendinousus) for Mirandesa calves of 9 mo old, while the calves slaughtered in late spring had significantly lower cholesterol content in longissimus lumborum compared to those processed in early autumn (Pestana et al., 2012). Further, different feeding systems may also vary the cholesterol level in veal with lower cholesterol content in longissimus thoracis of calves (∼6 mo old) reared on pasture with natural suckling compared to those fed with milk replacers and roughage (Miotello et al., 2009).

Vitamins and trace elements. Micronutrients such as choline and vitamins are of increasing interest to consumers due to their bioactive characteristics which may have significant implications in supporting the functioning of the human body and well-being (Wyness, 2016; Wallace et al., 2018). Previous studies observed similar vitamin E homologs (α- and γ-tocopherol) and β-carotene between longissimus thoracis, longissimus lumborum, and semitendinosus of Barrosã-PDO veal suggesting comparable antioxidant activity between these muscles (Mestre Prates et al., 2006). α-Tocopherol is the dominant type of vitamin E homolog present in meat, and its concentration in muscles has been suggested to vary with feeding systems (Yang et al., 2002; Skřivanová et al., 2007), geographical locations of farms (Costa et al., 2011), and cooking of meat (Perham et al., 2019). Concentrations of choline and B and D vitamins in veal were less explored in the literature. Feeding systems and muscle types could be the main drivers of variation in their concentrations. Higher levels of B and D vitamins were observed in veal from special-fed calves that received milk (soy/milk products) replacer formula diet until slaughter at 20 to 22 wk compared to commercial beef (recorded in the USDA database) (Perham et al., 2019).

Dietary intake of essential trace elements, such as iron, zinc, and selenium, is considered an important means for maintaining the proper functioning of the human body (Gupta & Gupta, 2014). Similar to other red meats, veal is a significant dietary source of essential trace elements, with the highest content found in zinc (Zn), followed by copper (Cu), selenium (Se), manganese (Mn), chromium, molybdenum, nickel, iron (Fe), and cobalt (Co) (Gálvez et al., 2019). The concentrations of trace elements in meat have been suggested to be associated with genetic factors (e.g., breed) (Miranda et al., 2018) and feeding systems (e.g., rearing methods and diets) (Blanco-Penedo et al., 2009). Significant variations of essential trace elements, especially Fe, Zn, and Cu, have also been observed among 7 veal cuts including shoulder clod, inside round, eye of round, bottom round, heel of round, knuckle, and tenderloin (Gálvez et al., 2019). Significantly higher levels of trace elements were found in tenderloin and shoulder clod, which could become a value-adding advantage to these muscles, especially for shoulder clod. The changes in trace elements between muscles may be due to the varied compositions of fiber types (slow- or fast-twitch fibers) in the different muscles (Pereira et al., 2017). Some essential trace elements (e.g., Co, Cu, Fe, Mn, and Se) were found to have negative relationships with protein contents of 10 commercial veal cuts (about 9-mo-old calves) including rib boneless entrecote, tenderloin, eye round, thick flank, tail of rump, chuck tender, shin, upper chuck, flank, and brisket (Pereira et al., 2017). It could be associated with the accumulation of trace elements in slow-twitch (oxidative) fibers along with increased levels of mitochondrial enzymes, myoglobin, and Fe-containing cytochrome to maintain the aerobic metabolic activities of these fibers (Choi & Kim, 2009). Further, increasing the age of calves at slaughter from 6 to 8 mo could result in higher levels of polyvalent metals (Magnesium [Mg], Zn, and Fe) with reduced Cu content in the loin muscles (Florek et al., 2015). Iron is the essential component for the synthesis of red blood cells, including hemoglobin, myoglobin, and cytochromes, and adequate intake of iron is necessary for the proper functioning and development of the human body (Speich et al., 2001).

Physical quality

Color. Color is one of the most important attributes affecting consumers’ purchasing decisions due to the perceived linkages with freshness and quality of meat. The color properties of meat are influenced by myoglobin content and its oxidation status, and by the ultimate pH of muscle. The value of veal is highly dependent on its color (Hulsegge et al., 2001; Ngapo & Gariépy, 2006). Different studies evaluated the veal color instrumentally using the CIELAB system (L*: lightness, a*: redness, b*: yellowness), generally with L* ranging from 42 to 51, a* from 8 to 14, and b* from 2 to 6 depending on the time postmortem, muscles, and production systems (Hulsegge et al., 2001; Lagoda et al., 2002; Vandoni & Sgoifo Rossi, 2009).

The meat from calves is associated with a pale or light red/pink color since traditionally this type of meat was obtained from young calves only fed on milk resulting in a relatively low level of myoglobin. The myoglobin content varies between muscles (Ngapo & Gariépy, 2006) and is affected by the diet; an increased iron intake may accumulate in muscles and result in a redder color of meat. Veal from grain-fed calves was darker and redder than that from milk-fed calves due to the lower iron content in milk compared to grain (Adams, 1975; Flynn, 1992). Similarly, pasture-fed (e.g., grass and clover) beef also has a darker color compared to grain-fed (Adams, 1975; Metson et al., 1979). Meat color from calves that grazed with their dams during the last period of rearing was darker than that from calves receiving their dams’ milk and concentrate (Ripoll et al., 2013). The use of different chelating (EDTA) and Fe-binding agents has been proposed to reduce iron absorption from the diet to maintain the typical light color of veal (Gariépy et al., 2004; Ngapo & Gariépy, 2006). On the other hand, limiting iron intake from the diet before slaughter (e.g., 60 d) also produced a pale color (Cui et al., 2017). Several other dietary treatments were evaluated, and their effects on meat color were inconsistent (Table 2). A similar color was observed in veal when the calves were fed with milk compared to grain or fed with milk ad libitum or in restricted amounts during the first 2.5 mo (Vieira et al., 2005). Color differences were not observed when comparing different proportions of concentrate in finishing veal diets (Cerdeno et al., 2006; Serrano et al., 2007; dos Santos et al et al., 2013). Darker meat color was observed in Holstein than in Australian beef breeds or Tudacana × Charolais than in Limousin calves (Aldai et al., 2012; Shabtay et al., 2021), which was suggested to be associated with the variations in the ultimate pH value.

Slaughter age significantly influences meat color, with a darker meat color (lower L*, but higher a* and b* values) observed with increasing slaughter age/weight (Monteiro et al., 2012; dos Santos et al., 2013; Marti et al., 2013; Albertí et al., 2014; Florek et al., 2015; Pike et al., 2019). In contrast, Yim and Hur (2019) observed that a* and b* values decreased in older calves, but that the L* value was not affected by animal age. On the other hand, the effect of weaning age on color is not conclusive (Table 2); weaning at a younger age could generate darker (3 vs. 7 mo) (Pateiro et al., 2013), lighter (90 vs. 180 d) (Blanco et al., 2008a), or similar meat color (90 vs. 150 d) (Blanco et al., 2008b, 2009). The effect of weaning age on color could be attributed to the change in the type of muscle fibers (Blanco et al., 2008a) with greater proportions of glycolytic fiber in calves weaned at a younger age. Further, weaning of Holstein calves at a lower weight (<90 kg) resulted in lower L* and b* relative to those weaned at higher weights (>100 kg) (Vavrišínová et al., 2020).

Additionally, meat color is also affected by the ultimate pH of the muscle. A darker meat color results from a high ultimate pH (Abril et al., 2001) due to insufficient muscle glycogen content at slaughter, which is mainly associated with diet and pre-slaughter stress (Immonen et al., 2000). On the other hand, a fast pH decline caused by electrical stimulation could lead to paler veal color at 24 h postmortem (Eikelenboom & Smulders, 1986; Warner et al., 2014).

Texture/tenderness. Tenderness is an important sensory attribute that contributes to the consumer satisfaction of beef. The tenderness of meat can be determined using sensory and instrumental analyses. Shear force, especially Warner-Bratzler shear force (WBSF) is a widely accepted measure for determining the tenderness of meat, which may provide relatively comparable results to sensory analysis (Otremba et al., 1999). Veal is characterized by being more tender (lower WBSF) than commercial beef (Monteiro et al., 2013; Domaradzki et al., 2017). This characteristic of veal could be attributed to its low content of total collagen and high content of soluble collagen compared to older animals as discussed earlier (Warner et al., 2021). The genotype of calves seemed to play a key role in determining the tenderness of veal (Table 1). Veal from the Limousin sired had lower tenderness (higher WBSF) than Charolais sired (Revilla & Vivar-Quintana, 2006; Severiano-Pérez et al., 2006) after 7 d of the postmortem aging (5.05/4.79 kg vs. 2.67/3.93 kg, young bulls/heifers from Limousin vs. Charolais). Holstein breed could produce more tender veal (lower WBSF) compared to the Slovak Simmental breed (3.99 vs. 10.81 kg.cm⁻² for loin muscle) (Vavrišínová et al., 2019a) and Hanwoo breed (4.39 vs. 7.89 kg) (Yim et al., 2015).

Marbling or IMF level has been suggested to positively affect the tenderness of meat (Nishimura et al., 1999), while such an impact seems to be more evident in older cattle than in veal, which could be due to its lean nature. Although the age at slaughter and sex could affect the fat content (as described earlier), the slight change in fat content in veal may not translate into an improvement in tenderness. Similar WBSF was observed in veal regardless of the sex and age of the calves (Revilla & Vivar-Quintana, 2006; Monteiro et al., 2013; Florek et al., 2015). The feeding system is another factor associated with the marbling mechanism; however, its impacts on tenderness were inconsistent (Table 2). Lower WBSF values were found in veal from grazing suckler calves compared to suckler calves supplemented with concentrate (Florek et al., 2013), while the opposite trend was also reported (Ripoll et al., 2013). No significant differences in WBSF values were observed in veal from calves reared with milk replacer plus roughage compared to those following an organic feeding system (Miotello et al., 2009) from calves reared on feedlot compared to pastures (dos Santos et al., 2013) or reared with milk compared to grain (Vieira et al., 2005). However, direct comparisons of absolute WBSF values across trials should be considered cautiously since they may be subject to unaccounted diverse sources of variation.

Water-holding capacity. The ability of meat to retain its water throughout the supply chain (e.g., production, processing, storage, distribution, and shelf display) and during cooking is referred to as water-holding capacity (WHC). WHC is a key quality attribute closely related to saleable value of meat (Castejón et al., 2015), microbial safety (den Hertog-Meischke et al., 1997), juiciness, and consumer liking of meat (Torley et al., 2000; Adzitey & Nurul, 2011). Meat products with poor WHC commonly lead to increased weight losses from drip/purge (i.e., drip/purge loss) and during the cooking process (i.e., cook loss). Breed and age of the calves at slaughter have been suggested to cause variations in the WHC of veal, although results were inconsistent (Table 1). Veal from the Slovak Simmental breed had higher drip loss (2.31% vs. 1.54%) and similar cook loss compared to Holstein in longissimus thoracis (Vavrišínová et al., 2019b). Higher cook losses and lower WHC of veal from the Hanwoo breed were observed compared to Holstein in the longissimus dorsi (% cook loss: 32.28 vs. 16.83; % WHC: 41.50 vs. 60.93) and semimembranosus muscles (% cook loss: 35.85 vs. 20.83; % WHC: 39.26 vs. 58.72) (Yim et al., 2015). However, a similar cook loss in veal meat was obtained regardless of the breed and sex (Severiano-Pérez et al., 2006). In terms of age, veal from older animals (8 mo old) had better WHC with lower cook loss compared to younger calves (5 to 7 mo old) (Yim & Hur, 2019). However, a lower cook loss was found when veal (12 mo old) was compared to beef from mature animals (15 to 30 mo old) (Monteiro et al., 2013). Inconsistent findings were also reported with higher drip losses and lower cook losses observed in 6-mo-old compared to 8-mo-old calves (Florek et al., 2015). No difference in cook loss and drip loss was found between ages (140, 160, and 190 d) (Tarantola et al., 2003) and weights at slaughter (Mandell et al., 2001). Generally, weaning strategies (e.g., weaned/non-weaned and weaning age) (Oliete et al., 2006; Bispo et al., 2010a; Pateiro et al., 2013) and feeding system (feedlot/pasture) (dos Santos et al., 2013) had minimal impacts on the WHC (cook loss and drip loss) of veal; only in one study the WHC of milk-fed veal was found to be higher than that of grain-fed veal (Vieira et al., 2005).

Consumer perception and sensory quality

Consumer quality perception of beef including veal is complex, dynamic, and increasingly influenced by extrinsic attributes such as price, origin, animal welfare, and environmental impact of meat production among others. However, sensory characteristics of food including meat remain the main purchase and repeat purchase consumer criteria (Calkins & Hodgen, 2007; New Zealand Trade and Enterprise, 2021). Resano et al. (2018) argued that few studies focused on evaluating consumers’ demand for veal in general, and more specifically from vealers (e.g., age between 8 and 10 mo). The authors highlighted that regional origin, empowered by local breed, and health information were more important than tenderness in Europe for experienced consumers, while younger consumers valued “tenderness guarantee.” The high variability in meat quality results in consumer difficulties in forming clear quality expectations. However, an “experience guarantee” label in consistently tender products would in part contribute to enhancing the factors that influence consumers’ purchasing decisions (Resano et al., 2018). Severiano-Pérez et al. (2006) evaluated the parameters affecting consumers’ choice of veal, indicating the light color of raw meat and odor, taste, tenderness, and juiciness of cooked veal as main attributes. Since color preferences for raw meat commonly vary between countries and by regions within the same country (Grunert, 1997), gaining an understanding of consumer perception and preferences in target markets for the color of veal from pasture-finished animals would be recommended.

Consumers perceive differences in overall liking of meat and meat products mainly through the assessment of juiciness, tenderness, and flavor (Grunert et al., 2004; Miller, 2020). For beef, consumer research before the 1990s showed that tenderness was the main driver of liking, while more recent research has shown that if tenderness and juiciness are at acceptable levels, the flavor becomes the main driver of beef consumer liking (Miller, 2020). Veal is expected to be tender and juicy and the flavor is significantly milder than beef from older animals. Different authors evaluated the relationships between muscle characteristics and meat quality, including sensory attributes. Serra et al. (2004) evaluated the eating quality of meat from yearling bulls and reported that meat odor and flavor were slightly positively correlated with carcass fatness and IMF, while overall tenderness and juiciness were positively correlated and negatively affected by the cooking loss. Furthermore, beef from forage-based systems tends to be higher in lean-type flavors, such as beef identity, bloody/serumy, metallic, and liver-like, and lower in lipid-derived flavors, such as fat-like and cardboardy (Sitz et al., 2005; Calkins & Hodgen, 2007; Miller, 2020). Miller (2020) indicated that consumers responded similarly to the differences in tenderness, but the flavor is more affected by cultural and environmentally learned behaviors in some countries. Thus, understanding consumer flavor preferences for grass-fed veal would be critical to meeting those preferences. The limited published data regarding the eating quality of veal produced from grazing systems highlight the need to evaluate those sensory attributes by domestic and target international consumers and their segments. More specifically, what are consumer preferences and the relative importance of credence (e.g., country of origin, animal welfare, environmental outcomes, and pastoral farming), search (e.g., overall appearance and color), and experience (e.g., tenderness and taste) attributes of veal from pastoral systems for domestic and international markets? For instance, are consumers willing to preferentially purchase veal from pastoral systems with a darker color and potentially a different taste than traditional European, Asian, or North American veal? Moreover, labeling and/or certification schemes can support signaling credence attributes to veal consumers.

Tailoring meat quality through farm management

As discussed in the previous section, the impacts of breed on veal quality are mainly on carcass characteristics, color, and tenderness, with minor effects on other traits such as pH, WHC, and some nutritional components (e.g., protein, moisture, fat, and trace elements). Feeding systems and weaning strategies also affected carcass characteristics and color of veal, but they have a significant effect on its nutritional composition as well, especially the FA profile. Further, the sex and age of calves at slaughter play a minor role in determining the quality of veal, with marginal changes observed mainly in color, fat content, and FA composition. These on-farm factors affect different aspects of veal quality, which may render opportunities to tailor certain quality attributes through applying different farm management systems and practices in response to the demands from different markets. For instance, selecting beef sires with genetic merits for improved growth, higher levels of marbling, and higher dressing percentages could result in larger and heavier cuts with improved quality. The right feeding system needs to be considered with the genotype since suckler calves (with the dam) were found to have lower weight gain than those fed with concentrate and hay regardless of the breeds (Bispo et al., 2010a; Ripoll et al., 2013). Lower marbling has been linked with grazing calves and forage-fed compared to feedlots or concentrate-fed (dos Santos et al., 2013).

Manipulation of feeding regime and weaning strategies are also relevant if the production goal is to boost the nutritional value of veal. For example, veal from grass-fed animals has been suggested to provide a more favorable n-6/n-3 ratio and level of n-3 PUFA and α-tocopherol compared to calves finished with farm products (e.g., hay, straws, oats, barley, or wheat) (Pestana et al., 2012). In concentrate-based diets, supplementation with linseed increased C18:3 n-3, conjugated linoleic acids (CLA) c-9, t-11, and other n-3 PUFA (Albertí et al., 2014; Gómez et al., 2015; Barahona et al., 2016; Morittu et al., 2021), and CLA supplementation further increased its proportion in the FA profile (Gómez et al., 2015; Barahona et al., 2016). The supplementation with maize in both dry and moist ensiled form led to a beneficial effect on the FA profile by increasing the proportions of MUFA and PUFA at the expense of SFA in veal (Sosin-Bzducha et al., 2012). However, adding linseed oil (4%) into the feed could increase n-3 PUFA content in veal meat and fat (González et al., 2014). Similarly, Vavrišínová et al. (2013) also observed that adding maize silage to a concentrate diet resulted in higher levels of n-3 PUFA, especially long-chain PUFA (eicosapentaenoic acid and docosahexaenoic acid, i.e., 20:5 n-3 and C22:6 n-3, respectively), and reduced n-6/n-3 ratio in veal. On the other hand, weaning practice and different weaning ages/weights could affect the FA composition, especially PUFA, although the results were conflicting. Based on the findings, nonweaned or early-weaned animals may provide a more favorable FA profile in veal with higher levels of MUFA and PUFA and lower SFA compared to late-weaned calves (Bispo et al., 2010b; Bispo et al., 2011).

Pre-rigor biochemical and biophysical interventions

The unique features of veal such as the lighter weight of the carcass, the resultant smaller sizes of the primal and subprimal cuts, and the relative leanness and tenderness of the meat compared to meat from older animals should be considered in any applied intervention to improve the quality or add value to the carcass.

Biochemical interventions revolve around the manipulation of the temperature and pH of muscles at rigor. The rates of temperature and pH decline are affected by various pre-rigor environments (e.g., application of electrical stimulation and carcass chilling rates) which determine the rate at which muscles attain rigor and convert to meat (Balan et al., 2019; Rhee & Kim, 2001). Muscles tend to cold-shorten when they enter rigor at temperatures below 10°C, resulting in tough meat, while muscle proteins denature at high rigor temperatures, resulting in faster deterioration in the quality attributes of meat such as color and WHC (Farouk & Swan, 1998; Bekhit et al., 2007). Calf carcasses have a relatively thin fat cover, which is prone to be cooled down faster than mature animals, thus caution should be paid to the chilling rate of calf carcasses to prevent cold-shortening of muscles. The pH/temperature window for the optimum meat quality for the smaller and leaner carcasses from yearling calves of 10 to 12 mo is unknown. However, based on the outcomes of previous studies, an early postmortem intervention that limits the pre-slaughter and immediate post-slaughter electrical inputs to those associated with stunning and immobilization should be sufficient when combined with rigor temperatures between 12°C and 15°C to optimize the eating quality and processing attributes of vealers (Farouk & Swan, 1998; Bekhit et al., 2007).

Biophysical interventions involve the physical manipulation of the muscle pre-rigor, including the way carcasses are hung while the muscles are undergoing rigor and the physical manipulation of the individual muscles using various restructuring methods. It has long been established that pre-rigor muscles can enter rigor with different degrees of contraction and meat from relaxed muscles are more tender relative to those from shortened or contracted muscles (Locker, 1960). This understanding has led to the development of many techniques to prevent pre-rigor muscles from contracting or to stretch these muscles to obtain relaxed ones during their conversion to meat (Sørheim & Hildrum, 2002). Some of these techniques include the suspension of carcasses from the Achilles tendon (the common industry practice) and its variants including the Tenderstretch and Tendercut processes. The former method involves the suspension of the carcass from the aitch bone (Obsturator foramen) instead of the traditional Achilles tendon, while the latter involves the severance at the 12^th thoracic vertebrae in beef carcass perpendicular to the vertebral column, ensuring the skin, adipose tissue, intercostal muscle, and connective tissue are all severed, leaving only the longissimus muscle to be maximally stretched (Wang et al., 1994; Claus et al., 1997; Farouk et al., 2009a).

The lower value cuts of veal such as the primal and subprimal from the fore- and hindquarters of a veal carcass can be hot-boned pre-rigor and manipulated to add value. Hot-boned muscles, because they are in a pre-rigor state, can be physically stretched to alter sarcomere length and tenderness in a manner analogous to the on-carcass Tenderstretch system of pelvic suspension. Manipulating hot-boned meat also offers some unique advantages such as portion control (Figure 1, unpublished data), which allows otherwise irregular muscle shapes to be manipulated to produce a regular (usually cylindrical) shape of the product. When muscle stretching is applied in conjunction with the optimal pre-rigor temperature/pH conditions, improved meat appearance and eating quality benefits may be realized.

Figure 1.

Digital photographs of control (left) and stretched (right) eye of round (A, semitendinosus), flat (B, biceps femoris), and insides corner cut (C, semimembranosus). These muscles were stretched and shaped pre-rigor using a proprietary stretching device.

Postmortem aging

Postmortem aging is a well-known processing technique to improve the tenderness and flavor of meat. There are 2 types of aging in general including wet- and dry-aging. Extensive studies were performed on wet-aging and mostly using beef from cattle over 18 to 24 mo of age. Based on the limited research performed on young cattle, veal of different ages (5, 6, 7, and 8 mo), genotype, and sex showed similar tenderization rates (Florek et al., 2015; Yim & Hur, 2019), whereas veal from young calves (e.g., ≤5 mo) had better initial tenderness (Ngapo & Gariépy, 2006; Domaradzki et al., 2017), suggesting different aging strategies would be needed for veal slaughtered at different ages to achieve favorable tenderness levels. The muscle of interest is also an important factor affecting the implementation of aging strategies. A minimum period of 4 d for loin muscle and 8 d for silverside of milk-fed Holstein calves (∼160 kg carcass weight) was recommended to obtain a perceivable tenderizing effect (Baldi et al., 2015). A minimum of 10 to 14 d of aging was suggested for veal raised on milk-based diets (Aldai et al., 2012; Ripoll et al., 2013; Florek et al., 2015). However, longer aging times seemed to be more favorable for producing veal with more homogeneous quality and minimizing variations due to other on-farm factors such as genetics (Monsón et al., 2004; Sañudo et al., 2004) and weaning strategies (Oliete et al., 2006). Aging could also increase color attributes (L*, a*, b*, and hue) of veal, resulting in intense color with a more pink hue (Oliete et al., 2006; Florek et al., 2009; Ripoll et al., 2013; Florek et al., 2015).

Dry-aging is another aging technique being developed for adding value to meat products by creating characteristic flavor profiles (Zhang et al., 2022). Dry-aging is traditionally performed without any packaging to encourage aerobic maturation and dehydration, which are the key contributors toward characteristic dry-aged meat flavors (Zhang et al., 2022). Although dry-aged meat is still a niche product, the intense roasted, nutty, sweet, and umami flavors of dry-aged meat command a premium price in the marketplace (Kim et al., 2018; Zhang et al., 2021b). Dry-aged meat flavors can be tailored by adopting different aging regimes and strategies (e.g., age-n-dry) based on the meat types and flavor characteristics of interest (Zhang et al., 2022; Zhang et al., 2023a; Zhang et al., 2023c). Given the fact that veal is generally more tender but leaner and with a milder flavor than standard commercial beef, developing a unique flavor profile using the dry-aging technique may increase the consumer acceptability of veal products for niche markets. The flavor profile of dry-aged veal is expected to be distinctive from Prime beef due to its low-fat content. Dry-aging of lean beef has been suggested to produce value-added beef with acceptable quality and oxidative stability during frozen storage (Zhang et al., 2019, 2021a). So far, limited studies have applied dry-aging on meat from young cattle, especially calves within 1 y of age. However, these studies focused either on the impacts of dietary supplements (Maggiolino et al., 2021) or on adding value to low-value cull cow meat (Barragán-Hernández et al., 2022). Dry-aging of striploin from Angus × Simmental cull cows (∼12 mo old) improved salty taste and sour-dairy flavor with reduced livery flavor compared to the wet-aged (Barragán-Hernández et al., 2022). However, whether dry-aging of veal could be a viable strategy to improve the quality and develop a desirable flavor preferred by consumers warrants future research.

Chilled and frozen storage

Chilled and frozen storage are common practices in the meat industry to maintain a sustainable supply of safe meat products locally and satisfy the demands from overseas markets throughout the year. However, preserving the fresh quality of meat is always challenging since the rich nutrient composition and high moisture level of meat make it susceptible to quality deterioration during storage. The storage life (chilled/frozen) of veal products has not been well studied. Veal has a relatively lower fat content compared to commercial beef, suggesting a lower oxidation potential with a possibly longer shelf life. However, storage could have significant impacts on the color properties of meat, which is the key indicator of freshness to consumers, despite the lower concentration of myoglobin and the pale color of veal. The use of different packaging formats such as vacuum packaging, modified atmosphere packaging (MAP), and film overwrapping during shelf display was suggested to have greater effects on the quality of veal compared to feeding systems, especially on the color properties (Ripoll et al., 2013). A MAP with high oxygen composition (80%) resulted in a shorter storage life (<1 wk) compared to vacuum packaging and overwrapping since the significant decrease of redness and chroma resulted in an increased hue angle. The color of the veal packaged with film overwrapping changed similarly compared to vacuum packaging. However, vacuum-packaged veal had lower metmyoglobin content and the highest redness following 13 d of storage, which implies that veal packaged in vacuum experienced a lower degree of discoloration. Decreasing the oxygen level of MAP to 46% resulted in similar color properties during 14 d of shelf storage, while reducing lipid and protein oxidation compared to 70% oxygen (De Palo et al., 2014). The quality deterioration could be further slowed down by using packaging materials with a lower oxygen transmission rate (De Palo et al., 2013). More advanced packaging systems such as active and intelligent packaging (Realini & Marcos, 2014; Domínguez et al., 2018; Li et al., 2022) could be considered for extending the shelf life of veal. For instance, oxidation and microbial spoilage are 2 key factors resulting in quality deterioration during storage; thus, developing an antimicrobial and antioxidant dual-functions active packaging system could be advantageous to both chilled and frozen veal products with improved storage life. Similarly, intelligent packaging systems such as indicators and sensors of time-temperature, integrity and freshness of packaged veal can monitor and inform the condition of the product during storage (Realini & Marcos, 2014).

Freezing is an effective means of being widely used for preserving the quality of meat. Although freezing meat can provide a much longer shelf life compared to chilling, frozen meat is always perceived as an inferior quality product by consumers with lower prices on the market (Zhang et al., 2023b). The issue of frozen meat is mainly with the crystallization of water in meat which results in some quality changes when meat is thawed, such as discoloration and drip loss (Leygonie et al., 2012), while the impacts of freezing on the quality of veal products have not been well-defined. Many studies have been conducted to elucidate the factors responsible for the quality deterioration of thawed meat and to develop technologies and processing regimes to improve the thawed meat quality to be as good as fresh (Lu et al., 2022). There is a regime involving aging and freezing as an integrated process (aging before freezing or aging after freezing) being developed, which demonstrated the potential to improve the quality of thawed meat and produce frozen meat with comparable quality to fresh-never-frozen meat (Farouk et al., 2009b, 2009c; Kim et al., 2011; Coombs et al., 2017). Such a regime can be tailored to suit different types of meat, muscles, and ultimate quality of interest through altering aging methods, conditions, and the sequence of aging and freezing/thawing (Zhang et al., 2023b). A regime involving a short aging (3 d at 4°C) before or after frozen storage (5 wk at −20°C) compared to aging only for 5 d was tested on veal (∼10 mo old), and a higher drip loss was observed (Moreno et al., 2007). Such outcomes suggested that different strategies may be needed for freezing lean meat like veal. For example, aging conditions (time and temperature) for veal before/after freezing need to be optimized to obtain the most favorable effects of this regime. Further, novel freezing and thawing technologies such as magnetic field and ultrasound have demonstrated the ability to improve the quality of thawed meat (Choi et al., 2015; Bhargava et al., 2021). However, the viability of using these technologies to produce thawed veal with high quality warrants future research.