Active packaging in practice: fish 389 8 P SS-200E/Air G-100/Air ZPT-10OE/A b)with soluble gas stabilisation(SGS) J- SS-200E/SGS o-G-10/SGS ZPT-IOOE/SGS Storage time( days) Fig. 18. 1 Effects of different oxygen absorbers on the growth of psychotrophic bacteria in salmon fillets stored at 1C a) packaged in air or b)SGS treatment with CO r to packaging u=Ageless SS oxygen absorber for high aw foods, Ageless ZPT oxygen absorber for dry foods, O= Ageless G combined oxygen absorber and carbon dioxide emiiter, and o= package without absorber(Sivertsvik et al. 1999) bserved in packages combining SGS with the combined O2 absorber and co emitter(Agelss G-100)1.e, the packages with most CO2 inside the package. The fastest microbial growth was observed in salmon stored in air without absorbers and in air with Ageless SS-200 and ZPT-100 O2-absorbers. These samples were
observed in packages combining SGS with the combined O2 absorber and CO2 emitter (Agelss G-100) i.e., the packages with most CO2 inside the package. The fastest microbial growth was observed in salmon stored in air without absorbers and in air with Ageless SS-200 and ZPT-100 O2-absorbers. These samples were Fig. 18.1 Effects of different oxygen absorbers on the growth of psychotrophic bacteria in salmon fillets stored at 1ºC a) packaged in air or b) SGS treatment with CO2 prior to packaging ❏ Ageless SS oxygen absorber for high aw foods; ■ Ageless ZPT oxygen absorber for dry foods; ❍ Ageless G combined oxygen absorber and carbon dioxide emiiter; and ● package without absorber (Sivertsvik et al. 1999) Active packaging in practice: fish 389
390 Novel food packaging techniques microbiologically spoiled after 13 days of storage. The effects of the absorbers and packaging method were not significant on the sensory evaluation scores but multiple comparisons confirmed the findings of the microbiological analyses The SGS samples were evaluated as better compared to air samples on cooked flavour, cooked odour and texture, but got slightly lower scores on raw odour evaluation Samples packaged with G-100 absorber/emitter gave the best cooked sensory scores, while samples without absorber got the lowest cooked sensory scores On raw odour the samples packaged with G-100 and without absorbers were evaluated as better than samples with SS-200 and ZPT-100 absorbers. No differences were observed in the colour of the samples, in contrast to the reddish colour change observed when packaging perch and pike perch fillets with the Ageless G-100 COz-emitters(Ahvenainen et al., 1997). They observed the same shelf-life for fresh perch and pike perch fillets packaged with G-100 as for traditional MAP using an anoxic high CO2 atmosphere, and 2-4 days longer shelf-life when compared with over-wrap or vacuum packaging. However colour change and a smell of raw liver in the raw fillets in the active packages was observed. This was not observed in the traditional MA-packages. No differences between the two packaging technologies were observed after cooking of the fish The commercial CO2 emitters usually contain ferrous carbonate and a metal ide catalyst alth though non-ferrous variants are available, absorbing the O2 and producing equal volumes of CO2. Carbon dioxide could also be produced inside the packages after packaging by allowing the exudates from the product to react with a mixture of sodium carbonate and citric acid inside the drip pad, an approach used successfully for cod fillets(Bjerkeng et al. 1995) increasing shelf-life as compared to traditional MAP, even when using a low gas head space in the package. The Verifrais package manufactured by Codimer, which has been used for extending the shelf-life of fresh meats and fish, is a similar concept(Day 1998). This package consists of a standard MAP tray but has a perforated false bottom under which a porous sachet containing sodium bicarbonate/ascorbate is positioned. When exudate from packed meat or fish drips onto the sachet, CO2 is emitted and counteracts package collapse due to the CO2 solubility in the food 18.4 Active packaging: water control Excess moisture is a major cause of food spoilage and different humidity absorbers are used to protect dried products from humidity damage. However, these absorbers have a limited effect on fish products. Several companie manufacture moisture drip absorbent pads, sheets and blankets for liquid water control in watery foods such as meat, fish, poultry, fruit and vegetables Moisture drip absorber pads or false-bottomed trays are commonly placed under packaged fresh meat, fish, poultry and prepared fruit to absorb unsightly tissue drip discharge. Larger sheets and blankets are used for absorption of melted ice
microbiologically spoiled after 13 days of storage. The effects of the absorbers and packaging method were not significant on the sensory evaluation scores but multiple comparisons confirmed the findings of the microbiological analyses. The SGS samples were evaluated as better compared to air samples on cooked flavour, cooked odour and texture, but got slightly lower scores on raw odour evaluation. Samples packaged with G-100 absorber/emitter gave the best cooked sensory scores, while samples without absorber got the lowest cooked sensory scores. On raw odour the samples packaged with G-100 and without absorbers were evaluated as better than samples with SS-200 and ZPT-100 absorbers. No differences were observed in the colour of the samples, in contrast to the reddish colour change observed when packaging perch and pike perch fillets with the Ageless G-100 CO2-emitters (Ahvenainen et al., 1997). They observed the same shelf-life for fresh perch and pike perch fillets packaged with G-100 as for traditional MAP using an anoxic high CO2 atmosphere, and 2–4 days longer shelf-life when compared with over-wrap or vacuum packaging. However, colour change and a smell of raw liver in the raw fillets in the active packages was observed. This was not observed in the traditional MA-packages. No differences between the two packaging technologies were observed after cooking of the fish. The commercial CO2 emitters usually contain ferrous carbonate and a metal halide catalyst although non-ferrous variants are available, absorbing the O2 and producing equal volumes of CO2. Carbon dioxide could also be produced inside the packages after packaging by allowing the exudates from the product to react with a mixture of sodium carbonate and citric acid inside the drip pad, an approach used successfully for cod fillets (Bjerkeng et al. 1995) increasing shelf-life as compared to traditional MAP, even when using a low gas headspace in the package. The Verifrais package manufactured by Codimer, which has been used for extending the shelf-life of fresh meats and fish, is a similar concept (Day 1998). This package consists of a standard MAP tray but has a perforated false bottom under which a porous sachet containing sodium bicarbonate/ascorbate is positioned. When exudate from packed meat or fish drips onto the sachet, CO2 is emitted and counteracts package collapse due to the CO2 solubility in the food. 18.4 Active packaging: water control Excess moisture is a major cause of food spoilage and different humidity absorbers are used to protect dried products from humidity damage. However, these absorbers have a limited effect on fish products. Several companies manufacture moisture drip absorbent pads, sheets and blankets for liquid water control in watery foods such as meat, fish, poultry, fruit and vegetables. Moisture drip absorber pads or false-bottomed trays are commonly placed under packaged fresh meat, fish, poultry and prepared fruit to absorb unsightly tissue drip discharge. Larger sheets and blankets are used for absorption of melted ice 390 Novel food packaging techniques