The effect of oxygen content on flavour and chemical changes during aseptic storage of whole milk after ultra-high-temperature processing

Thomas, Elmer L.; Burton, H.; Ford, J. E.; Perkin, A. G.

doi:10.1017/s0022029900015326

Cited by 46 publications

(27 citation statements)

References 13 publications

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“…The dissolved oxygen content of the permeate was not measured, but may have been relatively high if conditions during UF were turbulent. The presence of oxygen leads to a disappearance of the cooked flavour of UHT milk, which has been correlated with the oxidation of free sulphydryl groups (Thomas et al, 1975;Fink and Kessler,1986;Andersson and Ôste, 1992).…”

Section: Sensory Qua Litymentioning

confidence: 98%

Nutritional, sensory and physico-chemical characterization of protein-standardized UHT milk

Rattray

Gallmann

Jelen³

1997

Lait

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Summary -The protein content of 1.7% fat milk was standardized 'downwards' from -3.4% to values in the range -3.2-2.6%, by mixing with ultrafiltration (UF) permeate obtained from skim milk or quarg acid whey. Normal or protein-standardized milk products were subjected to direct (150 "C for 2.7 s) or indirect (138 "C for 1 s) ultra-high temperature (UHT) heat treatments and stored at 4 or 25 "C for up to 12 weeks. Standardization with skim milk permeate caused no change in the milk pH (6.7) and ail milk products had excellent stability during direct or indirect UHT heating. Upon storage at 4 or 25 "C for up to 12 weeks no age gelation occurred, and increases in apparent viscosity and sedimentation were minimal. Nutritional quality was slightly reduced by the addition of skim milk permeate, due mainly to minor decreases in the content of protein, calcium, phosphorus and potassium. Sensory quality was similar to normal UHT milk, as shown by periodic triangle sensory tests. The use of acid whey permeate for downward protein standardization led to a better profile of micronutrients, compared to milk with skim milk permeate. In other respects its use was unsatisfactory; although the pH shift upon addition of acid whey permeate to milk was minor (from pH 6.7 to pH 6.50-6.65), neutralization to pH 6.8 was required to avoid protein coagulation during direct or indirect UHT heating. In both direct or indirect UHT milk, high apparent viscosity and excessive sedimentation developed upon storage and off-flavours were unacceptably strong.protein standardization / URT milk / skim milk permeate / acid whey permeate Résumé -Caractérisation nutritive, sensorielle et physico-chimique de lait URT standardisé en protéine. La teneur en protéines du lait partiellement écrémé (1,7 % MG) a été standardisée à la baisse depuis -3,4 % à 3,2-2,6 % par addition de perméat provenant du traitement par ultrafiltration de lait écrémé ou de lactosérum obtenu lors de la fabrication de quarg. Les échantillons lactés ordinaires et standardisés en protéines ont subi un traitement ultra-haute température (UHT) selon une méthode de contact direct (2,7 s à 150 "C) ou indirect (15 s à 138 "C) avant d'être stockés pour une durée de 12 semaines à 4 "C ou 25 oc. La standardisation avec perméat de lait écrémé n'a produit aucun

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Section: Sensory Qua Litymentioning

confidence: 98%

Nutritional, sensory and physico-chemical characterization of protein-standardized UHT milk

Rattray

Gallmann

Jelen³

1997

Lait

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“…Later studies indicate that the beneficial effect of oxygen at >1.0 ppm on flavor is limited in duration relative to the probable life of the milk so as to be completely outweighed by the adverse nutritional effects. 54 Apart from catalyzing oxidized flavor, light also induces activated or sunlight flavor in milk. Described also by terms such as "burnt" and "cabbagey," the off-flavor compound has been postulated as methional originating from methionine as represented below: Detectable at a level of 0.5 ppm, concentration of this compound depends on the intensity of light, duration of exposure, and nature of the packaging material in which milk is stored.…”

Section: E Milk and Milk Productsmentioning

confidence: 99%

Requirements for foods packaged in polymeric films∗

Rizvi

Perdue

1981

C R C Critical Reviews in Food Science and Nutrition

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The requirements of barrier properties of packaging materials against environmental factors vary with food products. The chemical, physical, and biological mechanisms of food deterioration due to environmental factors, vital properties required in packaging materials, and developments in progress and future trends to maintain the required standard of food quality have been critically reviewed. Theoretical and experimental results for a variety of food products in relation to the properties of the packaging materials are discussed. Methods of prediction of food stability and their industrial applications are also emphasized by specific examples.

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“…24 High initial dissolved oxygen levels in milk have previously been found to promote the loss of free sulphydryl groups, with the greatest rate of decline coinciding with a rapid decrease in the dissolved oxygen concentration. 23 The treatment samples exhibited a decrease in dissolved oxygen content of 43% during the first 4 weeks of storage. The greater rate of decline is attributed to scavenging of oxygen by the prototype ZerO 2 TM present in the activated OSFL.…”

Section: Dissolved Oxygenmentioning

confidence: 94%

“…In indirectlyprocessed UHT milk, an initial dissolved oxygen content of 8.9 mg/l is sufficient to deplete ascorbic acid and folic acid levels within 4 weeks of ambient temperature storage. 23 Oxidation of volatile sulphydryl-containing compounds is also responsible for the dissolved oxygen decrease. These compounds are liberated from whey proteins in the milk, particularly b-lactoglobulin, that are denatured during UHT processing.…”

Section: Dissolved Oxygenmentioning

confidence: 99%

Active packaging of UHT milk to prevent the development of stale flavour during storage

Perkins

Zerdin²,

Rooney³

et al. 2006

Packag Technol Sci

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Indirectly processed UHT milk was packaged in IntaseptTM aseptic pouches with (treatment) or without (control) oxygen-scavenging film and stored for 14 weeks at 26 ± 0.3°C. Samples were analysed at 0, 4, 8 and 14 weeks for dissolved oxygen, stale flavour volatiles (methyl ketones and aldehydes) and free fatty acids. Discriminative subjective analysis of odour by a consumer panel was also conducted. The oxygen-scavenging film was shown to significantly (p < 0.05) reduce dissolved oxygen content by 23-28% during storage. Significant reductions of 23-41% were also observed for some stale flavour volatiles, including three methyl ketones and two aldehydes. Free fatty acid levels remained far below threshold values, indicating that lipolytic rancidity would not interfere with the subjective analysis. However, the consumer panel failed to detect a significant difference in odour between the treatment and control samples. INTRODUCTIONUHT milk has been shown to have a flavour that is undesirable to many consumers. 1-3Some researchers attribute this mainly to the development of a 'stale' or 'oxidized' flavour defect that arises within a month of storage and increases in intensity as time progresses. [4][5][6] Lipid oxidation in the milk produces methyl ketones and saturated aldehydes which contribute to this stale flavour. [7][8][9][10][11] Initial concentrations of these carbonyl compounds are generally greater in UHT milk that has been indirectly processed rather than directly processed. 12Previous attempts at preventing stale flavour formation in UHT milk have included the addition of antioxidants such as ascorbic acid, 4 butylated hydroxy anisole (BHA) 6 and bioflavanoids. 13 An alternative is active packaging incorporating oxygen scavengers. In the past, this has usually been in the form of sachets inserted into the food package. For liquid foods it is preferable to have the scavenger incorporated into the package itself to allow for a greater contact surface with the product.14 Maloba et al. 15 have used an oxygenscavenging film containing polyfuryloxirane to improve the oxidative stability of sunflower oil. In other studies, a film containing a reducible organic compound was used to scavenge oxygen from yoghurt in order to improve the viability of probiotic bacteria, 16 and a similar oxygen-scavenging film was used to decrease the rate of ascorbic acid loss in orange juice. 17The aim of this investigation was to modify a commercially available aseptic package to include an oxygen-scavenging film, and monitor its effect on stale flavour volatiles during ambient storage when used to package indirectly UHT-processed full-cream milk. EXPERIMENTAL Preparation of packagingSample packaging consisted of Intasept TM (VisyPak, Melbourne, VIC, Australia) gusseted pouches (340 × 225 mm) comprising a metallized polyester(PET)/linear low-density polyethylene(LLDPE) outer web and a LLDPE inner web. Half of the pouches were modified to incorporate a prototype ZerO 2 TM oxygen scavenging film laminate (OSFL). The OSFL was inserted...

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The effect of oxygen content on flavour and chemical changes during aseptic storage of whole milk after ultra-high-temperature processing

Cited by 46 publications

References 13 publications

Nutritional, sensory and physico-chemical characterization of protein-standardized UHT milk

Nutritional, sensory and physico-chemical characterization of protein-standardized UHT milk

Requirements for foods packaged in polymeric films∗

Active packaging of UHT milk to prevent the development of stale flavour during storage

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