T.A. Kenny

Effect of rapid and conventional cooling methods on the quality of cooked ham joints

Three cooling regimes, vacuum (VC), blast (BC) and slow cooling (SC), were compared for their effect on cooling rate, weight loss and quality of large cooked ham joints. Vacuum cooling reduced the cooling rate (70-4°C) significantly (P<0.05) in comparison to the other methods; mean cooling times for cooked hams (5-6 kg) were 1.9 h for VC, 11.7 for BC and 14.3 for SC. However, VC gave an increased chill loss (P<0.05) of ca. 11% compared to ca. 4% for the other methods due to evaporative moisture loss. Sensory panels found that VC hams were tougher and less juicy (P<0.05). Shear force measurements and texture profile analysis also showed the vacuum cooling to have a toughening effect on the cooked ham. While vacuum cooling had an adverse effect on quality and yield, it was the only one that conformed to recent safety guidelines for cooked meat joints of a reduction in temperature to 5°C inside 10 h. The cooling conditions used do not reproduce full-scale industrial practice, however, the effects found serve as an indicator of the potential benefits and drawbacks of vacuum cooling for cooked meat joints.

The effect of injection level on the quality of a rapid vacuum cooled cooked beef product

Abstract The influence of vacuum cooling (VC) on the quality of a cooked beef product injected with brine over a range of levels was studied as compared with a control water immersion (WI) cooling system. Samples were cooked in an oven at 82°C until core temperatures reached 72°C and then cooled to core temperatures of 4°C. Mean results showed that VC was very rapid (64 min) compared to 300 min for WI. Chill loss for VC products was on average 10.55% and not affected by injection level compared to only 1.88% for WI samples. Total yield in VC samples was improved as injection level increased and was comparable to WI samples at injection levels of greater than 130% of green weight. Sensory analysis indicated that overall WI samples were more tender and juicy than VC samples up to 130% injection, while VC samples had a better overall colour acceptability and flavour. However, high injection levels in VC samples resulted in increased saltiness and unfavorable sensory scores. Instrumental texture results indicated that increasing injection level decreased Warner–Bratzler shear force required for the vacuum cooled beef product.

Analysis and classification of commercial ham slice images using directional fractal dimension features

This paper presents a novel and non-destructive approach to the appearance characterization and classification of commercial pork, turkey and chicken ham slices. Ham slice images were modelled using directional fractal (DF(0°;45°;90°;135°)) dimensions and a minimum distance classifier was adopted to perform the classification task. Also, the role of different colour spaces and the resolution level of the images on DF analysis were investigated. This approach was applied to 480 wafer thin ham slices from four types of hams (120 slices per type): i.e., pork (cooked and smoked), turkey (smoked) and chicken (roasted). DF features were extracted from digitalized intensity images in greyscale, and R, G, B, L(∗), a(∗), b(∗), H, S, and V colour components for three image resolution levels (100%, 50%, and 25%). Simulation results show that in spite of the complexity and high variability in colour and texture appearance, the modelling of ham slice images with DF dimensions allows the capture of differentiating textural features between the four commercial ham types. Independent DF features entail better discrimination than that using the average of four directions. However, DF dimensions reveal a high sensitivity to colour channel, orientation and image resolution for the fractal analysis. The classification accuracy using six DF dimension features (a(90°)(∗),a(135°)(∗),H(0°),H(45°),S(0°),H(90°)) was 93.9% for training data and 82.2% for testing data.

The effects of different cooking regimes on the cook yield and tenderness of non-injected and injection enhanced forequarter beef muscles.

The aim was to investigate the effect of different cooking regimes on the cook yield and tenderness of non-injected and brine injected (0.5% residual NaCl) bovine M. triceps brachii caput longum (TB), M. supraspinatus (SP) and M. pectoralis profundus (PP). Injected and non-injected TB, SP and PP muscle sections (400 g) were (a) conventionally oven cooked to 72 degrees C or cooked slowly (using a Delta10 programme) to 72 degrees C or (b) cooked in a water bath to 72 degrees C or cooked in a water bath to 55 degrees C and held at this temperature for 2 h before heating to 72 degrees C. In addition, injected PP muscle sections were oven cooked to 69 degrees C and held at this temperature for up to 12 h. Slow cooking using a Delta10 programme had no significant (P<0.05) effect on WBSF values of injected or non-injected SP and TB muscles but significantly (P<0.05) decreased the WBSF values of injected and non-injected PP muscles when compared to conventional cooking. Slow cooking significantly (P<0.05) increased % cook yield of injected PP, SP and TB muscles. Staged cooking significantly (P<0.05) decreased the WBSF values and had no significant effect on sensory tenderness ratings of non-injected TB, SP and PP muscles and injected PP muscles. Staged cooked injected or non-injected PP, SP and TB muscles had lower % cook yield values than those cooked straight to 72 degrees C. Increasing the cooking time of injected PP muscles at 69 degrees C to 8 and 12 h decreased % cook yield, decreased WBSF values and increased sensory tenderness ratings. It also alleviated the problem of residual chewiness which was evident in PP muscles cooked using the other regimes.

Performance of cold-set binding agents in re-formed beef steaks.

Four cold-setting gel-forming binding agents were compared in preparation of re-formed steaks from strips of each of two muscles, M. triceps brachii-caput longum (TB) from the shoulder, and M. pectoralis profundus (PP) from the brisket, of steer forequarter. The binding agents, which were commercial preparations, were Activa, containing transglutaminase enzyme as active ingredient, Fibrimex, containing the blood plasma fractions fibrinogen and thrombin, Textor, containing a modified starch, and alginate, containing sodium alginate and Ca(++). Binding of the cooked steaks and of slices therefrom, was satisfactory for the first three of the above but relatively weak for the alginate agent. Colour of steaks was affected by binder, in that Activa and Textor treatments gave lighter, redder and yellower (higher L*, a*, b* values) steaks than did the other two. Overall acceptability ratings by taste panels corresponded with those for flavour in the case of TB steaks, with Activa and Fibrimex samples scoring highest (P<0.05). For the less tender PP steaks, the highest acceptability score was for the Textor samples, reflecting their scoring best for tenderness. Warner-Bratzler shear force values corresponded with tenderness ratings in that Textor samples had lowest shear values for both muscles, but the differences were not significant. The overall conclusion, considering cohesion, appearance, cooking yield and sensory quality of the products, was that the Activa binder performed best and would facilitate the production of good-quality chilled re-formed beef steaks from various low-value beef muscles, and without addition of sodium chloride if so desired.

Development of a modified dry curing process for beef

The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (P<0.001). The control and vacuum pulsed samples were tougher (P<0.001). Vacuum tumble and tumble only treatments gave higher acceptability (P<0.001). Based on these findings for M. supraspinatus, indicating that the vacuum tumble treatments gave the best results, further testing of this method was conducted using the M. biceps femoris in addition to the M. supraspinatus. Cured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), P<0.001) decreased over storage time in M. biceps femoris. Vacuum tumble treatment increased (P<0.05) redness in M. supraspinatus. Results obtained demonstrate the benefits of vacuum tumbling over the other physical treatments as a method for accelerating the dry curing process, producing dry cured beef products with enhanced organoleptic quality and increased yields.

The effect of sodium lactate, potassium lactate, carrageenan, whey protein concentrate, yeast extract and fungal proteinases on the cook yield and tenderness of bovine chuck muscles

This study evaluated the efficacy of injection with enhancement solutions containing sodium lactate (NaLac), potassium lactate (KLac), carrageenan, whey protein concentrate (WPC), yeast extract or fungal proteinases alone or in combination with NaCl at increasing the tenderness and cook yield of bovine M.supraspinatus and M. tricepsbrachii caput longum. Muscle sections (400g) were injected with enhancement solutions at an injection rate of 110% to give specific residual concentrations as follows: 0.5% NaCl; 2% NaLac; 2% KLac; 0.5% NaCl+1 or 2% NaLac; 0.5% NaCl+1% KLac; 0.5% NaCl+0.4% sodium tripolyphosphate (STPP)+2% NaLac; 0.5% NaCl+0.4% STPP, 1.5% WPC+/-0.5% NaCl, 1.0% carrageenan+/-0.5% NaCl, 0.5% yeast extract or 0.0005% and 0.001% fungal enzymes. Injection with solutions containing sodium or potassium lactates (alone or in combination with NaCl and STPP), WPC, carrageenan and yeast extract significantly (P<0.05) decreased WBSF values and increased sensory tenderness ratings, compared to non-injected controls. All of these ingredients in water also significantly (P<0.05) increased cook yield with the exception of yeast extract which had no significant effect. The fungal enzymes in a water carrier acted as effective tenderising agents in both muscles but when used at the higher level resulted in a significant decrease in percentage cook yield. Injection of the chuck muscles with these ingredients and water represents an effective method of improving their tenderness and in most cases also increasing percentage cook yield.

Effects of enhancement procedures on whole and re-formed beef forequarter muscles.

Beef Supraspinatus and Triceps brachii muscles were subjected to three enhancement and/or re-forming treatments: (i) injected whole @ 15%w/w with salt-phosphate solution; (ii) injected and re-formed; (iii) injected with added flavouring and re-formed. The treated muscles were compared to whole uninjected controls. All injection treatments reduced shear force values of cooked samples and in most cases these reductions were reflected in sensory panel tenderness and chewiness ratings. For example, shear values for Supraspinatus were 83N/g in control samples and 50 in whole injected samples, while corresponding sensory panel tenderness ratings were 3.6 and 5.2. Enhanced samples did not differ from controls in sliceability or in colour and binding ratings, indicating that enhancement combined with re-forming can give an acceptable roast beef product. There were no differences in drip loss and very few differences in colour L*, a* and b* values for raw samples between any of the treatments. Addition of beef stock did not result in higher flavour ratings by sensory panels. Whole injected samples scored higher for flavour than both control (p<0.01) and injected+re-formed (p<0.05) samples.

The effect of hot-boning and reduced added phosphate on the processing and sensory properties of cured beef prepared from two forequarter muscles

The functionality of pre-rigor beef was investigated in terms of the effects of phosphate reduction and curing of hot-boned meat on the processing and sensory properties of relatively low-value muscles, M. infraspinatus (IS) and M. pectoralis profundus (PP), from the forequarter. Muscles were excised within 90 min post-mortem (HB) or, from chilled carcasses, 24 h post-mortem (CB), and were injected to 115% of green weight with brine containing phosphate and were vacuum tumbled continuously for 2 h. Hot-boning gave lower total yield of cooked meat for both muscles. Hot-boned PP joints had slightly higher (P<0.05) cook loss than cold-boned. Reduction of added phosphate (from sodium tri-polyphosphate) from 0.3% to 0.15% of cured meat had detrimental effects on colour; joints containing the conventional 0.3% were lighter (P<0.001) and redder for both muscles. Hot-boning gave PP joints which were rated less tender by sensory panels, corresponding with higher (P<0.001) hardness TPA values, higher (P<0.05) Warner-Bratzler shear force (WBSF) values and shorter (P<0.05) sarcomere lengths. Effects of phosphate level and boning method were less in IS joints. In these, hot-boning gave products that were rated by sensory panel as slightly more tender but there was no effect on TPA or WBSF values. Furthermore, total yields from hot-boned products did not reflect the expected increase in functionality and reducing added phosphate during processing had a detrimental effect in binding and forming of joints.

Mechanical tenderisation of beef muscles for use in re-formed joints made with a cold-set binder

Three treatments, blade tenderisation (BT), needle tenderisation (NT) and enhancement by brine injection+vacuum-pulsing (VP), were applied to each of two muscles from beef forequarter, M. pectoralis profundus and M. supraspinatus, and two from the round of the hindquarter, M. semimembranosus and M. vastus lateralis. The tenderised muscles and non-treated controls were re-formed into joints using a cold-set bonding agent and tested as steaks cut from the joints. NT and VP gave a similar degree of tenderisation, as indicated by W-B shear force and taste panel, while BT had a lesser but still significant effect. Cook loss from steaks was increased by BT and NT treatments for the, tougher, forequarter but not the hindquarter muscles. The overall conclusion was that NT and VP treatments are more effective than BT but that the 3 methods are satisfactory for tenderisation of beef for production of re-formed steaks. Reduced redness and higher bacterial numbers arising from VP could render this treatment more suitable for re-formed steaks for catering than for retail sale. A supplementary trial showed that slices from roasted VP-treated re-formed joints (as distinct from grill-cooked steaks tested in the main trial) were better in sliceability and equal to or better in sensory quality than those from commercial whole-muscle round roasts purchased in a supermarket.