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Effect of tray liners on the drip loss of lamb chops during retail display
Meat Science 27 (1990) 87-90
Research Note Effect of Tray Liners on the Drip Loss of Lamb Chops During Retail Display
A BSTRA CT The amount of drip lost by lamb chops during display was affected by the type of tray liner used. bt one stud)' involving chilled and frozen~thawed meat. the use of an absorbent paper liner #wreased the drip loss and influenced whether or not the quantity of drip was affected by freezing~thawing. In another study, thawed chops heldfor 24 h on plastic coated tra)'s without liner or on a plastic coated liner had less than 2% drip loss, whereas adjacent chops from the same loin processed and held in the same way but displayed on liners of absorbent paper or paper pouches of diatomaceous earth lost 4"3% and 5"6% drip. respectively. This effect of the material in contact with the meat should be considered when reporting drip loss data and when comparing results with those of other researchers.
INTRODUCTION The loss of fluid, or drip, from meat is commonly determined by measuring the weight of liquid exuded or by loss of weight of the meat sample. In experiments on the display life of lamb chops, the material (liner) on which the chop rested during display was found to greatly affect drip loss as measured by a change in sample weight. Two experiments are reported in this paper to illustrate this point and to bring this effect to the attention of other meat researchers. 87 Meat Science0309-1740/90/$03.50~. 1990ElsevierSciencePublishersLtd, England.Printed in Great Britain
88
1I. J. Moore
MATERIALS AND METHODS
Comparison of thawed and fresh chops with and without liners This study was designed to assess the effect of absorbent tray liners on the display characteristics of frozen/thawed lamb chops. For each treatment (chilled vs thawed) there were eight carcasses, two chops per loin. The loins were either chilled or had been frozen at - 2 0 ° C for 1 week, then thawed overnight at 3°C. Two adjacent chops of 20 m m thickness were cut by bandsaw from each loin. One chop was placed on a plastic coated Plix tray (Donagheys, Auckland, New Zealand) with no liner and the other placed on the same type of tray with a folded absorbent paper towel (Handee Towels, Caxton Paper Co., Auckland, New Zealand). Chops were packaged four to a tray, and did not contact each other. Chops and tray were overwrapped with oxygen permeable d-film (W. R. Grace, Porirua, New Zealand, O T R > 2000 ml/m2/24 h at 25°C). Other than the presence or absence of a tray liner, all handling, i.e. temperature, lighting, display time, was identical for each pair of chops. Each chop was weighed before packaging and at the end of display life, and the per cent weight loss calculated. Chops were displayed at 3°C under Philips Deluxe 32 ° lighting until at least one chop of each pair was rejected by an experienced panel on the basis ofcolour; then both were removed and the drip measured. The maximum display life of the chops was 4 days. A straightforward analysis of variance was carried out.
Effect of different tray liners on drip loss Frozen loins from five carcasses stored for approximately 1 year were obtained from an export meat plant and were thawed overnight at 3°C. Four adjacent 20 mm chops were cut from each thawed loin and were randomly assigned to one of four treatments: (a)
No absorbent liner. Chops were placed directly onto Plix plastic coated trays. (b) Keep" Fresh Filter (SMS Filter GmbH, West Germany). Chops were placed individually on pouches of absorbent paper containing diatomaceous earth. Absorbence factor of pad = 3.62. (c) Absorbent paper. Chops were placed on a folded paper towel (Handee Towel). Absorbence factor of liner = 6.40. (d) Plastic coated absorbent liner. Chops were placed on an absorbent liner, one side of which was coated with plastic, which was perforated with microscopic pores (Printpac Ltd, Auckland). Absorbence factor of liner = 4.33. Chops were placed on the plastic coated side.
Effect of tray liners on drip loss of lamb chops
89
Absorbence factor = weight of water retained by liner after submerging in water for 1 min divided by initial weight of liner. Chops were weighed before packaging and placed two or three to a tray on the relevant pad and overwrapped with d-film. They were held for 24 h in a single layer at 3°C, after which the chops were again weighed and the per cent drip loss during the 24 h period was calculated.
RESULTS AND DISCUSSION In the first experiment chops placed on absorbent paper liners lost significantly more drip than chops placed directly on the tray (Table 1). With the unlined tray, there was no significant difference between the drip loss of chilled and frozen/thawed samples, but when absorbent paper liners were present, thawed chops lost significantly more drip than chilled. This illustrates that experimental results can be influenced by such mundane items as the type of tray liner used. It also illustrates that the water in thawed chops is more loosely bound than that of chilled chops since more of it can be removed by the capillary action of the absorbent liner. In the second experiment, using thawed chops and three types of tray liner, drip loss was significantly greater from chops held on absorbent paper and the liner containing diatomaceous earth than that from chops held on the bare tray or on the plastic coated liner with microscopic holes (Table 2). These studies show that the use of absorbent liners encourages fluid loss from meat samples if the absorbent material is in contact with the meat, probably by capillary action. When large amounts of drip are lost, the chop develops a shrunken, concave surface, adversely affecting the meat appearance; therefore, the use of a very absorbent liner may affect not only drip loss but sample appearance. TABLE i Drip (Per cent Weight Loss) from Chilled and Thawed Lamb Chops during Retail Display. Chops were Packaged with and without a Tray Liner of Absorbent Paper
Treatment
Per cent drip
Chilled"
Frozen,'thawed~
No liner
Lbler
No liner
Liner
0.25
1.08
0-26
1-39
a 16 chops from 8 carcasses. SED = 0-069. Liner p < 0.01; Chilled/thawed p < 0-01 ; Chilled/thawed x liner p < 0.01.
90
V.J. Moore TABLE 2 Per cent Drip from Thawed Lamb Chops after 1 Day's Display. Chops were Packaged with No Liner or One of Three Liners Liner
Per cent drip
No liner
SMS ~
1'62
5"63
Absorbent Papercoated paper with plastic
4.30
1"52
a SMS liners consisted of diatomaceous earth. SED = 0.523 p < 0.001. Five carcasses per treatment, all treatments from four adjacent chops from the same loin. The magnitude of the effect of liners on drip loss obtained in these studies could easily overwhelm any differences due to treatment. Published reports show there are considerable differences between the amounts o f weight lost during display or storage. Henry et aL (1983) obtained drip losses o f between 0.5 and 3.4% for chilled lamb chops, whereas losses obtained by Jeremiah et aL (1972) in a similar study ranged from 3"1 to 7"3%. In our studies, drip loss during display (without liner) for chilled, non-frozen lamb chops is usually below 1%. Is this difference due to the presence o f an absorbent tray liner in the above papers or to other factors? Because there is no mention o f tray liners in most papers, it is impossible to make a reasoned comparison between treatment effects from various studies. The absorbence factor determined for the different liners in this study does not correlate with the drip loss from the chops since it provides a measure of the water holding capacity o f the liners rather than an indication of the capillary forces exerted by the liner.
REFERENCES Henry, K. G., Savell, J. W., Smith, G. C., Ehlers, J. G. & Vanderzant, C. (1983). J. Food Sci., 48, 1735. Jeremiah. L. E., Smith, G. C. & Carpenter. Z. L. (1972). J. Food ScL, 37, 457. V, J. Moore Meat Imhtsto, Research Institute o f New Zealand, Inc., PO Box 617, Hamilton, New Zealand
{Received 17 January 1989; accepted 13 June 1989)
Research Note Effect of Tray Liners on the Drip Loss of Lamb Chops During Retail Display
A BSTRA CT The amount of drip lost by lamb chops during display was affected by the type of tray liner used. bt one stud)' involving chilled and frozen~thawed meat. the use of an absorbent paper liner #wreased the drip loss and influenced whether or not the quantity of drip was affected by freezing~thawing. In another study, thawed chops heldfor 24 h on plastic coated tra)'s without liner or on a plastic coated liner had less than 2% drip loss, whereas adjacent chops from the same loin processed and held in the same way but displayed on liners of absorbent paper or paper pouches of diatomaceous earth lost 4"3% and 5"6% drip. respectively. This effect of the material in contact with the meat should be considered when reporting drip loss data and when comparing results with those of other researchers.
INTRODUCTION The loss of fluid, or drip, from meat is commonly determined by measuring the weight of liquid exuded or by loss of weight of the meat sample. In experiments on the display life of lamb chops, the material (liner) on which the chop rested during display was found to greatly affect drip loss as measured by a change in sample weight. Two experiments are reported in this paper to illustrate this point and to bring this effect to the attention of other meat researchers. 87 Meat Science0309-1740/90/$03.50~. 1990ElsevierSciencePublishersLtd, England.Printed in Great Britain
88
1I. J. Moore
MATERIALS AND METHODS
Comparison of thawed and fresh chops with and without liners This study was designed to assess the effect of absorbent tray liners on the display characteristics of frozen/thawed lamb chops. For each treatment (chilled vs thawed) there were eight carcasses, two chops per loin. The loins were either chilled or had been frozen at - 2 0 ° C for 1 week, then thawed overnight at 3°C. Two adjacent chops of 20 m m thickness were cut by bandsaw from each loin. One chop was placed on a plastic coated Plix tray (Donagheys, Auckland, New Zealand) with no liner and the other placed on the same type of tray with a folded absorbent paper towel (Handee Towels, Caxton Paper Co., Auckland, New Zealand). Chops were packaged four to a tray, and did not contact each other. Chops and tray were overwrapped with oxygen permeable d-film (W. R. Grace, Porirua, New Zealand, O T R > 2000 ml/m2/24 h at 25°C). Other than the presence or absence of a tray liner, all handling, i.e. temperature, lighting, display time, was identical for each pair of chops. Each chop was weighed before packaging and at the end of display life, and the per cent weight loss calculated. Chops were displayed at 3°C under Philips Deluxe 32 ° lighting until at least one chop of each pair was rejected by an experienced panel on the basis ofcolour; then both were removed and the drip measured. The maximum display life of the chops was 4 days. A straightforward analysis of variance was carried out.
Effect of different tray liners on drip loss Frozen loins from five carcasses stored for approximately 1 year were obtained from an export meat plant and were thawed overnight at 3°C. Four adjacent 20 mm chops were cut from each thawed loin and were randomly assigned to one of four treatments: (a)
No absorbent liner. Chops were placed directly onto Plix plastic coated trays. (b) Keep" Fresh Filter (SMS Filter GmbH, West Germany). Chops were placed individually on pouches of absorbent paper containing diatomaceous earth. Absorbence factor of pad = 3.62. (c) Absorbent paper. Chops were placed on a folded paper towel (Handee Towel). Absorbence factor of liner = 6.40. (d) Plastic coated absorbent liner. Chops were placed on an absorbent liner, one side of which was coated with plastic, which was perforated with microscopic pores (Printpac Ltd, Auckland). Absorbence factor of liner = 4.33. Chops were placed on the plastic coated side.
Effect of tray liners on drip loss of lamb chops
89
Absorbence factor = weight of water retained by liner after submerging in water for 1 min divided by initial weight of liner. Chops were weighed before packaging and placed two or three to a tray on the relevant pad and overwrapped with d-film. They were held for 24 h in a single layer at 3°C, after which the chops were again weighed and the per cent drip loss during the 24 h period was calculated.
RESULTS AND DISCUSSION In the first experiment chops placed on absorbent paper liners lost significantly more drip than chops placed directly on the tray (Table 1). With the unlined tray, there was no significant difference between the drip loss of chilled and frozen/thawed samples, but when absorbent paper liners were present, thawed chops lost significantly more drip than chilled. This illustrates that experimental results can be influenced by such mundane items as the type of tray liner used. It also illustrates that the water in thawed chops is more loosely bound than that of chilled chops since more of it can be removed by the capillary action of the absorbent liner. In the second experiment, using thawed chops and three types of tray liner, drip loss was significantly greater from chops held on absorbent paper and the liner containing diatomaceous earth than that from chops held on the bare tray or on the plastic coated liner with microscopic holes (Table 2). These studies show that the use of absorbent liners encourages fluid loss from meat samples if the absorbent material is in contact with the meat, probably by capillary action. When large amounts of drip are lost, the chop develops a shrunken, concave surface, adversely affecting the meat appearance; therefore, the use of a very absorbent liner may affect not only drip loss but sample appearance. TABLE i Drip (Per cent Weight Loss) from Chilled and Thawed Lamb Chops during Retail Display. Chops were Packaged with and without a Tray Liner of Absorbent Paper
Treatment
Per cent drip
Chilled"
Frozen,'thawed~
No liner
Lbler
No liner
Liner
0.25
1.08
0-26
1-39
a 16 chops from 8 carcasses. SED = 0-069. Liner p < 0.01; Chilled/thawed p < 0-01 ; Chilled/thawed x liner p < 0.01.
90
V.J. Moore TABLE 2 Per cent Drip from Thawed Lamb Chops after 1 Day's Display. Chops were Packaged with No Liner or One of Three Liners Liner
Per cent drip
No liner
SMS ~
1'62
5"63
Absorbent Papercoated paper with plastic
4.30
1"52
a SMS liners consisted of diatomaceous earth. SED = 0.523 p < 0.001. Five carcasses per treatment, all treatments from four adjacent chops from the same loin. The magnitude of the effect of liners on drip loss obtained in these studies could easily overwhelm any differences due to treatment. Published reports show there are considerable differences between the amounts o f weight lost during display or storage. Henry et aL (1983) obtained drip losses o f between 0.5 and 3.4% for chilled lamb chops, whereas losses obtained by Jeremiah et aL (1972) in a similar study ranged from 3"1 to 7"3%. In our studies, drip loss during display (without liner) for chilled, non-frozen lamb chops is usually below 1%. Is this difference due to the presence o f an absorbent tray liner in the above papers or to other factors? Because there is no mention o f tray liners in most papers, it is impossible to make a reasoned comparison between treatment effects from various studies. The absorbence factor determined for the different liners in this study does not correlate with the drip loss from the chops since it provides a measure of the water holding capacity o f the liners rather than an indication of the capillary forces exerted by the liner.
REFERENCES Henry, K. G., Savell, J. W., Smith, G. C., Ehlers, J. G. & Vanderzant, C. (1983). J. Food Sci., 48, 1735. Jeremiah. L. E., Smith, G. C. & Carpenter. Z. L. (1972). J. Food ScL, 37, 457. V, J. Moore Meat Imhtsto, Research Institute o f New Zealand, Inc., PO Box 617, Hamilton, New Zealand
{Received 17 January 1989; accepted 13 June 1989)