Improved tenderness of alpaca carcasses using combined processing techniques

Abstract

Rapid growth within the Australian alpaca industry has increased interest in alpaca meat as a viable alternative to traditional fibre production, driving research into alpaca meat eating quality. However, product quality and inconsistency are limiting market growth. Meat quality is impacted by many factors throughout the supply chain, including pre-slaughter handling, processing conditions, packaging and cooking. In order to improve quality, the impact of these factors on alpaca needs to be considered. In order to address these knowledge gaps and maximize quality and efficiency throughout the alpaca meat supply chain, the following research was conducted. Three separate studies were conducted across three consecutive years in order to investigate the thesis aims.

The first study (Chp 2) sought to investigate the effects of season and post-transport resting on alpaca meat quality. A total of 160 castrated male huacaya alpacas (23 ± 1 month of age) were transported to slaughter over a 12-month period. Animals were transported in two groups of 20 per season to generate 8 replicate trials across the year. Immediately following transport, animals were allocated to one of two treatment groups at the abattoir (overnight pre-slaughter lairage or a seven-day pre-slaughter rest period with ad lib access to feed and water). Animals were processed under commercial conditions and chilled for 24 h prior to the removal of the m. Longissimus thoracis (LT) from the right-hand side of each carcase. Results indicated that alpaca meat quality varied across the year, with increased moisture loss through summer and spring and a trend toward improved summer tenderness. Resting alpacas for 7 days pre-slaughter had a negative effect on meat quality, with reduced muscle glycogen content and tenderness, and increased moisture loss.

The second study (Chp 3 and 4) investigated the effects of combining tenderstretching (TS) with medium voltage electrical stimulation (ES) during processing on tenderness, oxidation and eating quality traits of alpaca. Thirty-six castrated male huacaya alpacas (23 ± 1 month of age) were processed over 2 days, two months apart. Carcases were split and treatments applied to sides at random, in a 2×2 factorial arrangement. Treatments included; (1) Achilles Hung + No ES; (2) Achilles Hung + ES; (3) TS + No ES; and (4) TS + ES. After 24 hours chilling, carcase sides were broken down and the Longissimus thoracic et lumborum (LTL), Adductor femoris (AF), Semimembranosus (SM), Semitendinosus (ST) and Psoas major (TL) muscles were extracted for meat quality and consumer sensory evaluation. Results indicated that combined processing treatments improved alpaca meat SF and eating quality across the carcase, while having no detrimental effects on colour stability and oxidation. However, alpaca LTL SF values remained high comparative to that of hind quarter muscles.

The third study (Chp 5) aimed to build on the findings study one and two. The effect on alpaca meat quality from applying medium voltage ES in combination with TS to whole carcases was investigated, along with the effect of enzyme (actinidin) infusion on alpaca LTL quality. Thirty-six entire male huacaya alpacas (23 ± 1 month of age) were processed over two days, two weeks apart. Carcases were randomly allocated to one of two processing treatments; (1) Achilles hung + No ES, and (2) TS + ES, in order to investigate the effect of combined processing methods on whole alpaca carcases. After 24 h, carcases were broken down with both the left-and-right-hand-side LTL of each carcase allocated to one of three infusion treatments, including; (1) no infusion; (2) infusion with water, and; (3) infusion with enzyme. In addition, the SM from the right hind leg of each carcase was collected for meat quality evaluation. Results supported the use of combined TS with ES in commercial alpaca processing and indicated no advantages in infusing alpaca LTL with actinidin.

The results indicate that maximising on-farm feed quality and availability leading to slaughter and avoiding lengthy lairage periods after 4 h transportation will maximise alpaca carcase tenderness. Residual variation in quality across multiple muscles arising from intrinsic factors such as nutrition and pre-slaughter stress can be minimised through the application of ES and TS in combination. Due to the limitations in achieving optimal alpaca LTL tenderness, it is suggested that a fresh market for the product be avoided until consumers become more familiar with the novel meat, focussing instead on value added, ready to eat product development and sales through restaurant trade. Future areas of research for alpaca must focus on genetic influences and specific biochemical processes occurring during the toughening and tenderisation phases of processing in order to further the understanding of alpaca meat tenderness.