Heat-induced and other chemical changes in commercial UHT milks

Elliott, Anthony J.; Datta, Nivedita; Amenu, B.; Deeth, Hilton C.

doi:10.1017/s002202990500138x

Cited by 77 publications

(70 citation statements)

References 16 publications

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“…Obviously, ESL milk samples of poor quality had been manufactured using an indirect UHT process that had been reported to be cheaper (regarding investment and production costs) and more energy-efficient compared to the direct UHT heating techniques using injection or infusion systems. On the other hand, directly UHT-treated ESL milk suffers less heat damage than indirectly heated milk and can therefore be used in the production of ESL milk as an alternative to modern microfiltration techniques [10,15,18,24,25].…”

Section: Comparison Of Acid-soluble β-Lgmentioning

confidence: 99%

“…Furosine (NeoMPS PolyPeptide Laboratories Group, Strasbourg, France) was used as standard. Calibration (5,10,20,40,80, and 160 pmol·20 μL −1 injection volume) was performed by plotting peak area versus picomole of furosine. Concentrations of furosine were displayed as picomole, which were subsequently converted to the results given in mg·100 g −1 protein (Tab.…”

Section: Rp-hplc Analysis Of Furosinementioning

confidence: 99%

“…However, heating causes a significant loss of organoleptic and nutritional quality (e.g. vitamin destruction, precipitation of calcium phosphate, denaturation of whey proteins, and Maillard reaction) [2,8,10,11,22]. Furthermore, an undesirable precipitation of denatured proteins and minerals can be formed on the walls of heat exchangers [15,18,25].…”

Section: Introductionmentioning

confidence: 99%

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RP-HPLC analysis of furosine and acid-soluble β-lactoglobulin to assess the heat load of extended shelf life milk samples in Austria

Mayer

Raba

Meier

et al. 2010

Dairy Sci. Technol.

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-Recent trends to extend the shelf life of pasteurized milk, without the negative flavour normally associated with ultra-high-temperature (UHT) milk, have resulted in the development of extended shelf life (ESL) milk. Acid-soluble β-lactoglobulin (β-Lg) and furosine contents were chosen as relevant indicators for heat load of ESL milk products. RP-HPLC methods were developed using the same column (Symmetry 300™, Waters), which enabled the separation of whey proteins within 22 min; furosine was analysed using ion-pair RP-HPLC within 8 min. Electrophoresis was used as a high-throughput and cost-effective screening method to assess the impact of thermal processes on milk and to distinguish different categories of heat-treated milk samples. Liquid milk samples (n = 128; including 7 raw, 33 pasteurized, 71 ESL, and 17 UHT milk samples) were obtained from retail outlets in Austria and analysed. Only 45% of the analysed samples designated as ESL milk showed furosine contents < 40 mg·100 g −1 protein as well as acid-soluble β-Lg contents > 1800 mg·L −1 milk, which had been discussed as threshold levels for ESL milk. A further 55% of the analysed ESL milk samples had low acid-soluble β-Lg (< 500 mg·L −1 ) and high furosine contents (> 40 mg·100 g −1 protein), levels comparable to the excessive heat load of UHT milk. Thus, there is an urgent need for an EU regulation to define legal limits for the tolerable heat load of ESL milk as soon as possible.extended shelf life milk / β-lactoglobulin / furosine / RP-HPLC / electrophoresis Article published by EDP Sciences Résumé -Analyse de la furosine et de la β-lactoglobuline soluble à pH acide par RP-HPLC pour évaluer la charge thermique de laits de longue conservation en Autriche. La tendance actuelle visant à allonger la durée de conservation du lait pasteurisé, sans avoir les défauts de flaveur habituellement associés au lait UHT, a conduit au développement du lait de longue conservation ESL. Les concentrations en β-lactoglobuline soluble à pH acide (β-Lg) et en furosine ont été choisies comme indicateurs pertinents de la charge thermique des produits laitiers ESL. Des méthodes RP-HPLC ont été développées avec la même colonne (Symmetry 300™, Waters), qui a permis de séparer les protéines sériques en 22 min ; la furosine était analysée par RP-HPLC en paire d'ions en 8 min. L'électrophorèse a été utilisée comme méthode économique de criblage à haut débit pour évaluer l'impact des traitements thermiques sur le lait et pour distinguer différentes catégories d'échantillons de lait traité thermiquement. Les échantillons de lait liquide (n = 128 ; comprenant 7 échantillons de lait cru, 33 pasteurisé, 71 ESL et 17 UHT) ont été prélevés dans des points de vente en Autriche et analysés pour leur teneur en β-lactoglobuline et furosine. Seulement 45 % des échantillons analysés désignés comme lait ESL présentaient des teneurs en furosine inférieures à 40 mg·100 g −1 de protéine et des teneurs en β-lactoglobuline soluble à pH acide supérieures à 1800 mg·L, valeurs qui ont été disc...

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Section: Comparison Of Acid-soluble β-Lgmentioning

confidence: 99%

Section: Rp-hplc Analysis Of Furosinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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RP-HPLC analysis of furosine and acid-soluble β-lactoglobulin to assess the heat load of extended shelf life milk samples in Austria

Mayer

Raba

Meier

et al. 2010

Dairy Sci. Technol.

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“…Sakkas et al (2014) suggested that this group of effects includes degradation of lactose to organic acids and formation of lactulose, denaturation of whey proteins, destruction of vitamins and enzymes, hydrolysis of proteins and lipids and disturbance of calcium/phosphorus equilibrium. Other effects include cooked flavor and nutritional value loss due to new substances formed by the Maillard reaction, which continues during storage of heated milks (Elliott et al, 2005). The effect of heat treatments on the components of milk has been described.…”

Section: Introductionmentioning

confidence: 99%

Effects of Pasteurization and Ultra-High Temperature Processes on Proximate Composition and Fatty Acid Profile in Bovine Milk

Pestana¹,

Gennari²,

Monteiro³

et al. 2015

American J. of Food Technology

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The aim of this work was to evaluate the effects of pasteurization and ultra-high temperature processes on proximate and physicochemical composition, microbiological parameters and fatty acid profile in bovine milk. Raw, pasteurized and sterilized milks were collected at a dairy factory in the state of Rio Grande do Sul, Brazil. The samples were submitted to determination of moisture, protein, total fat, lactose, total solids, free-fat dry extract, urea, calcium, phosphorus, pH, acidity, density, fatty acid profile, somatic cell count and total bacterial count. Pasteurized and ultra-high temperature milks kept protein and lactose content similar to raw milk. Pasteurization and sterilization altered the composition of the milk slightly, decreasing total fat and total solids and increasing urea. These processes changed essentiality short-chain fatty acids (4:0, 6:0 and 8:0). High proportions of palmitic acid (18:0), oleic acid (18:1 n-9), stearic acid (18:0) and myristic acid (14:0) were found in all milks analyzed. The absence of large significant modifications on milk composition and fatty acid profile indicates that the processes could be applied without altering the nutritional value of the milk.

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“…De acordo com Browning et al (2001) e Elliott et al (2005), períodos de aquecimento e resfriamento prolongados durante o tratamento térmico podem resultar em pro dutos similares àqueles submetidos ao pro cesso de esterilização, visto os efeitos quí micos e biológicos agregados durante estas duas etapas. Portanto, é de se esperar que danos provoca dos pelo calor durante o tra tamento UHT sejam mais intensos em sis temas indiretos, quando comparado a sistemas diretos; uma vez que o dano causa do depende do tempo de exposição do produto ao calor (MORTIER et al, 2000).…”

Section: Resultsunclassified

Avaliação Do Índice De Soroproteína Não Desnaturada Como Um Indicador De Tratamento Térmico Para Leite Uht E Leite Em Pó

Oliveira¹,

Marinho²,

Zamagno³

et al. 2015

Revista do ILCT

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RESUMODurante o processamento térmico de produtos lácteos ocorrem diversas modificações químicas dentre as quais a desnaturação de soroproteínas é bastante evidente e estudada. Este fenômeno pode gerar gelificação em leite UHT e problemas de solubilização em leite em pó, dois importantes produtos lácteos amplamente difundidos no mercado nacional. O índice de soroproteína não-desnaturada (WPNI) pode ser uma ferramenta útil para avaliar o grau de severidade ao qual o leite está sendo submetido e, portanto, permite inferir sobre a ocorrência dos possíveis defeit os associados à desnaturação proteica. Neste estudo, verificou-se o teor de soroproteína não-desnaturada como indicador de tratamento térmico em leite submetido aos processamentos de ultrapasteurização e de secagem. As amostras comerciais de leite UHT e leite em pó ana lisadas apresentaram um intervalo de confiança de WPNI (2,39 ± 1,41) mg WPN.mL -1 e (2,63 ± 1,38) mg WPN.mL -1 , respectivamente. De acordo com a análise estatística de variância, todas as amostras avaliadas diferiram entre si com um p-valor < 0,001; sendo que 90% das amostras de leite UHT e 67% para as amostras de leite em pó foram classificadas como submetidas a médio tratamento térmico. Os dados obtidos permitiram inferir sobre a severidade do tratamento térmico associado a cada tipo de produto analisado e foram capazes de demonstrar a falta de padronização dos processos de tratamento térmico nas amostras estudadas, fato este que pode ter como consequência o desenvolvimento de características indesejáveis nos produtos ao longo do período de estocagem e comercialização.Palavras-chave: desnaturação; processamento térmico; qualidade; desidratação.

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Heat-induced and other chemical changes in commercial UHT milks

Cited by 77 publications

References 16 publications

RP-HPLC analysis of furosine and acid-soluble β-lactoglobulin to assess the heat load of extended shelf life milk samples in Austria

RP-HPLC analysis of furosine and acid-soluble β-lactoglobulin to assess the heat load of extended shelf life milk samples in Austria

Effects of Pasteurization and Ultra-High Temperature Processes on Proximate Composition and Fatty Acid Profile in Bovine Milk

Avaliação Do Índice De Soroproteína Não Desnaturada Como Um Indicador De Tratamento Térmico Para Leite Uht E Leite Em Pó

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