Development of a laboratory technique for the evaluation of protease enzymes activity in goat and sheep milk

Palomba, Raffaele; Formisano, Giorgio; Arrichiello, Assunta; Auriemma, Giuseppe; Sarubbi, Fiorella

doi:10.1016/j.foodchem.2016.10.125

Cited by 9 publications

(8 citation statements)

References 28 publications

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“…This finding highlight that the refrigerated storage changed the profile of the milk contaminants, increasing from ~10% to ~50% of the psychrotrophic population in milk, which was expected due to the low storage temperature (Sierra et al, 2009). Psychrotrophic microorganisms can produce proteases during refrigerated storage, which, when in high concentration, can destabilize the protein micelles leading to gel formation and protein precipitation, with a reduction of sensory quality (Palomba et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

Sodium reduction in “Requeijão cremoso” processed cheese made from fresh and refrigerated sheep milk

Dalmina

Malta

Silva

et al. 2022

Food Processing Preservation

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The characteristics of traditional and reduced‐sodium “Requeijão cremoso” processed cheese made from fresh sheep milk and refrigerated milk (4°C/5 days) were evaluated. Five days were established as the maximum time of storage of raw milk, reaching counts of 106 and 105 CFU/ml of mesophilic and psychrotrophic populations, respectively. The curds produced from refrigerated milk had lower fat content (~20%) and resulted in processed cheese with higher hardness, cohesiveness, and gumminess. The replacement of common emulsifying salt for reduced‐sodium salt led to a 50% sodium reduction in the product, with no changes in color, texture, and pH. The results showed that the storage of raw milk had an impact on the curd composition and the texture of processed cheese. On the other hand, the replacement of emulsifying salt only affected the mineral composition of the final product, being an interesting alternative to ensure low‐sodium content in processed cheese. Practical applications Studies on determining the limited period of raw sheep milk storage and the consequences on the final product are important for the sheep dairy chain, mainly because sheep milk is produced by smallholdings in many countries. Many producers need to store raw milk for days to accumulate a sufficient volume of milk for processing. In turn, sodium reduction is a global trend, thus knowledge about the impact of the replacement of emulsifying salt in processed cheese may encourage different dairy manufacturers to reformulate their products aiming to develop healthier products.

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Section: Resultsmentioning

confidence: 99%

Sodium reduction in “Requeijão cremoso” processed cheese made from fresh and refrigerated sheep milk

Dalmina

Malta

Silva

et al. 2022

Food Processing Preservation

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“…Proteolysis is produced by psychrotrophic microorganisms that grow at low temperature (≤7 • C) [86]. During the storage of pasteurized milk at 5 • C, these microorganisms play a critical role in the microflora formation and are responsible for several problems in pasteurized milk [86]. In good hygiene practices, the percentage of psychrotrophic microbial is lower than 10% of the total microbial flora in pasteurized milk.…”

Section: Determination Of Protease Activity In Pasteurized Buffalo Milkmentioning

confidence: 99%

Potential Activity of Aqueous Fig Leaves Extract, Olive Leaves Extract and Their Mixture as Natural Preservatives to Extend the Shelf Life of Pasteurized Buffalo Milk

Abdel-Aziz

Darwish

Mohamed

et al. 2020

Foods

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The aim of this study was to evaluate fig (Ficus carica L.) leaves’ extract (FLE), olive (Olea europaea L.) leaves’ extract (OLE), and their mixture (MLE), to extend the shelf life of pasteurized milk. OLE, FLE, and their mixture MLE (1:1) were added to the pasteurized milk in different concentrations (0.2%, 0.4%, and 0.6%). Several tests were then conducted to determine the activity of these extracts. The antioxidant activity as IC50 was determined by using DPPH radical assay. FLE showed higher IC50 (30.21 µg/mL) compared to the IC50 of OLE (22.43 µg/mL). Phenolic compounds were identified by using high-performance liquid chromatography (HPLC). The highest antimicrobial activity was obtained with 0.6% concentration. Organoleptic properties indicated that the addition of these extracts did not affect the sensory properties of pasteurized milk. Pasteurized milk treated with 0.6% of FLE, OLE, and MLE has significantly decreased (p ≤ 0.05) lipase and protease activity during the storage period, at 5 °C. The results indicated that extending the shelf life of pasteurized milk from 5 to 16 days was successfully achieved through using 0.6% of FLE, OLE, and MLE. The combination of the two extracts (MLE) provides an efficient and safe method to prolong the shelf life of pasteurized milk, without altering the properties of pasteurized buffalo milk.

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“…Non-specific protease activity of both casein and whey fractions isolated from raw and heated ruminant milk samples were determined as previously described (17)(18)(19) using azocasein (a protein coupled with diazotized aryl amines) as substrate.…”

Section: Determination Of Non-specific Protease Activitymentioning

confidence: 99%

Heat-Treatments Affect Protease Activities and Peptide Profiles of Ruminants' Milk

et al. 2021

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Proteases present in milk are heat-sensitive, and their activities increase or decrease depending on the intensity of the thermal treatment applied. The thermal effects on the protease activity are well-known for bovine milk but poorly understood for ovine and caprine milk. This study aimed to determine the non-specific and specific protease activities in casein and whey fractions isolated from raw bovine, ovine, and caprine milk collected in early lactation, and to determine the effects of low-temperature, long-time (63°C for 30 min) and high-temperature, short-time (85°C for 5 min) treatments on protease activities within each milk fraction. The non-specific protease activities in raw and heat-treated milk samples were determined using the substrate azocasein. Plasmin (the main protease in milk) and plasminogen-derived activities were determined using the chromogenic substrate S-2251 (D-Val-Leu-Lys-pNA dihydrochloride). Peptides were characterized using high-resolution liquid chromatography coupled with tandem mass spectrometry. The activity of all native proteases, shown as non-specific proteases, was similar between raw bovine and caprine milk samples, but lower (P < 0.05) than raw ovine milk in the whey fraction. There was no difference (P > 0.05) between the non-specific protease activity of the casein fraction of raw bovine and caprine milk samples; both had higher activity than ovine milk. After 63°C/30 min, the non-specific protease activity decreased (44%; P > 0.05) for the bovine casein fraction only. In contrast, the protease activity of the milk heated at 85°C/5 min changed depending on the species and fraction. For instance, the activity decreased by 49% for ovine whey fraction, but it increased by 68% for ovine casein fraction. Plasmin and plasminogen were in general inactivated (P > 0.05) when all milk fractions were heated at 85°C/5 min. Most of the peptides present in heat-treated milk were derived from β-casein and αS1-casein, and they matched the hydrolysis profile of cathepsin D and plasmin. Identified peptides in ruminant milk samples had purported immunomodulatory and inhibitory functions. These findings indicate that the non-specific protease activity in whey and casein fractions differed between ruminant milk species, and specific thermal treatments could be used to retain better protease activity for all ruminant milk species.

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Development of a laboratory technique for the evaluation of protease enzymes activity in goat and sheep milk

Cited by 9 publications

References 28 publications

Sodium reduction in “Requeijão cremoso” processed cheese made from fresh and refrigerated sheep milk

Sodium reduction in “Requeijão cremoso” processed cheese made from fresh and refrigerated sheep milk

Potential Activity of Aqueous Fig Leaves Extract, Olive Leaves Extract and Their Mixture as Natural Preservatives to Extend the Shelf Life of Pasteurized Buffalo Milk

Heat-Treatments Affect Protease Activities and Peptide Profiles of Ruminants' Milk

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