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Amer DA, Albadri AAM, El-Hamshary HA, Nehela Y, Makhlouf AH, El-Hawary MY, Awad SA. Changes in Sensory Properties, Physico-Chemical Characteristics, and Aromas of Ras Cheese under Different Coating Techniques. Foods 2023; 12:foods12102023. [PMID: 37238841 DOI: 10.3390/foods12102023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/30/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Ras cheese is one of the main hard cheeses in Egypt and is well-known worldwide. Herein, we investigated the potential effects of different coating techniques on the physico-chemical characteristics, sensory properties, and aroma-related volatile organic compounds (VOCs) of Ras cheese over a six-month ripening period. Four coating techniques were tested, including (I) uncoated Ras cheese (the benchmark control), (II) Ras cheese coated with paraffin wax (T1), (III) Ras cheese coated with a plastic film under a vacuum (PFUV; T2), and (IV) Ras cheese coated with a plastic film treated with natamycin (T3). Although none of the treatments significantly affected the salt content, Ras cheese coated with a plastic film treated with natamycin (T3) slightly reduced the moisture content over the ripening period. Moreover, our findings revealed that while T3 had the highest ash content, it showed the same positive correlation profiles of fat content, total nitrogen, and acidity % as the control cheese sample, indicating no significant effect on the physico-chemical characteristics of the coated cheese. Furthermore, there were significant differences in the composition of VOCs among all tested treatments. The control cheese sample had the lowest percentage of other VOCs. T1 cheese, coated with paraffin wax, had the highest percentage of other volatile compounds. T2 and T3 were quite similar in their VOC profiles. According to our GC-MS findings, thirty-five VOCs were identified in Ras cheese treatments after six months of ripening, including twenty-three fatty acids, six esters, three alcohols, and three other compounds identified in most treatments. T2 cheese had the highest fatty acid % and T3 cheese had the highest ester %. The development of volatile compounds was affected by the coating material and the ripening period of the cheeses, which played a major role in the quantity and quality of volatile compounds.
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Affiliation(s)
- Dina A Amer
- Department of Food Science and Technology, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt
| | - Abdinn A M Albadri
- Department of Biology, College of Science, King Khalid University, Abha 62529, Saudi Arabia
| | - Hanaa A El-Hamshary
- Department of Food Science and Technology, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt
| | - Yasser Nehela
- Department of Agricultural Botany, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt
- Department of Plant Pathology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA
| | - Abeer H Makhlouf
- Department of Agricultural Botany, Faculty of Agriculture, Minufiya University, Shibin El-Kom 32511, Egypt
| | - Mohamed Y El-Hawary
- Department of Food Science and Technology, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt
| | - Sameh A Awad
- Dairy Microorganisms and Cheese Research Laboratory (DMCR), Department of Dairy Science and Technology, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt
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Forler B, Horstmann G, Schäfer J, Michel C, Weiss A, Stressler T, Fischer L, Hinrichs J, Schmidt H. Effects of Protein, Calcium, and pH on Gene Transcription, Cell-Envelope Peptidase Activity of Lactococcus lactis Strains, and the Formation of Bitter Peptides. Foods 2021; 10:foods10071588. [PMID: 34359457 PMCID: PMC8307170 DOI: 10.3390/foods10071588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/16/2022] Open
Abstract
Calcium- and protein-rich fermented milk products, such as concentrated yoghurts and fresh cheeses, may contain undesired bitter peptides, which are generated by the proteolytic cleavage of casein. Up to now, it is not clear whether this process is caused by endogenous milk enzymes, such as plasmin and cathepsin D, or whether proteolytic enzymes from applied starter cultures, such as the lactococcal cell-envelope peptidase PrtP, are involved. A sensory analysis of fresh cheese products made from milk concentrates fermented with prtP-negative and -positive Lactococcus lactis strains revealed bitterness in the products fermented with prtP-positive L. lactis strains. Two prtP-positive strains, LTH 7122 and LTH 7123, were selected to investigate the effect of increased calcium concentrations (additional 5 mM and 50 mM CaCl2) at neutral (pH 6.6) and acidic (pH 5.5) pH-values on the transcription of the prtP gene and its corresponding PrtP peptidase activity in milk citrate broth (MCB). For both strains, it was shown that prtP transcription was upregulated only under slightly elevated calcium conditions (5 mM CaCl2) after 5 h of growth. In concordance with these findings, PrtP peptidase activity also increased. When higher concentrations of calcium were used (50 mM), prtP expression of both strains decreased strongly by more than 50%. Moreover, PrtP peptidase activity of strain LTH 7123 decreased by 15%, but enzymatic activity of strain LTH 7122 increased slightly during growth under elevated calcium concentrations (50 mM CaCl2). Fermentations of reconstituted casein medium with 3.4% (w/v) and 8.5% (w/v) protein and different calcium concentrations using strain LTH 7122 revealed no clear relationship between prtP transcription and calcium or protein concentration. However, an increase in PrtP peptidase activity under elevated protein and calcium conditions was observed. The activity increase was accompanied by increased levels of bitter peptides derived from different casein fractions. These findings could be a possible explanation for the bitterness in fermented milk concentrates that was detected by a trained bitter panel.
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Affiliation(s)
- Benjamin Forler
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany; (B.F.); (C.M.); (A.W.)
| | - Gudrun Horstmann
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 25, 70599 Stuttgart, Germany; (G.H.); (T.S.); (L.F.)
| | - Johannes Schäfer
- Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21, 70599 Stuttgart, Germany; (J.S.); (J.H.)
| | - Christina Michel
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany; (B.F.); (C.M.); (A.W.)
| | - Agnes Weiss
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany; (B.F.); (C.M.); (A.W.)
| | - Timo Stressler
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 25, 70599 Stuttgart, Germany; (G.H.); (T.S.); (L.F.)
| | - Lutz Fischer
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 25, 70599 Stuttgart, Germany; (G.H.); (T.S.); (L.F.)
| | - Jörg Hinrichs
- Department of Soft Matter Science and Dairy Technology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 21, 70599 Stuttgart, Germany; (J.S.); (J.H.)
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany; (B.F.); (C.M.); (A.W.)
- Correspondence: ; Tel.: +49-711-459-22305
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Begunova AV, Savinova OS, Rozhkova IV, Krysanova YI, Fedorova TV. In Vitro Assessment of Probiotic Potential and Functional Properties of Lactobacillus reuteri LR1. APPL BIOCHEM MICRO+ 2020. [DOI: 10.1134/s000368382005004x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Solieri L, De Vero L, Tagliazucchi D. Peptidomic study of casein proteolysis in bovine milk by Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.06.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Rai AK, Sanjukta S, Jeyaram K. Production of angiotensin I converting enzyme inhibitory (ACE-I) peptides during milk fermentation and their role in reducing hypertension. Crit Rev Food Sci Nutr 2018; 57:2789-2800. [PMID: 26463100 DOI: 10.1080/10408398.2015.1068736] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fermented milk is a potential source of various biologically active peptides with specific health benefits. Angiotensin converting enzyme inhibitory (ACE-I) peptides are one of the most studied bioactive peptides produced during milk fermentation. The presence of these peptides is reported in various fermented milk products such as, yoghurt, cheese, sour milk, etc., which are also available as commercial products. Many of the ACE-I peptides formed during milk fermentation are resistant to gastrointestinal digestion and inhibit angiotensin converting enzyme (ACE) in the rennin angiotension system (RAS). There are various factors, which affect the formation ACE-I peptides and their ability to reach the target tissue in active form, which includes type of starters (lactic acid bacteria (LAB), yeast, etc.), substrate composition (casein type, whey protein, etc.), composition of ACE-I peptide, pre and post-fermentation treatments, and its stability during gastrointestinal digestion. The antihypertensive effect of fermented milk products has also been proved by various in vitro and in vivo (animal and human trials) experiments. This paper reviews the literature on fermented milk products as a source of ACE-I peptides and various factors affecting the production and activity of ACE-I peptides.
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Affiliation(s)
- Amit Kumar Rai
- a Institute of Bioresources and Sustainable Development, Sikkim Centre , Sikkim , India
| | | | - Kumaraswamy Jeyaram
- b Microbial Resource Division , Institute of Bioresources and Sustainable Development , Manipur , India
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Production of Angiotensin-I-Converting-Enzyme-Inhibitory Peptides in Fermented Milks (Lassi) Fermented by Lactobacillus acidophillus with Consideration of Incubation Period and Simmering Treatment. Int J Pept Res Ther 2016. [DOI: 10.1007/s10989-016-9540-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Chen Y, Li C, Xue J, Kwok LY, Yang J, Zhang H, Menghe B. Characterization of angiotensin-converting enzyme inhibitory activity of fermented milk produced by Lactobacillus helveticus. J Dairy Sci 2015; 98:5113-24. [DOI: 10.3168/jds.2015-9382] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 03/15/2015] [Indexed: 11/19/2022]
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Wang J, Li C, Xue J, Yang J, Zhang Q, Zhang H, Chen Y. Fermentation characteristics and angiotensin I-converting enzyme-inhibitory activity of Lactobacillus helveticus isolate H9 in cow milk, soy milk, and mare milk. J Dairy Sci 2015; 98:3655-64. [PMID: 25892687 DOI: 10.3168/jds.2015-9336] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/14/2015] [Indexed: 01/17/2023]
Abstract
Lactobacillus helveticus isolate H9 demonstrated high angiotensin I-converting enzyme (ACE)-inhibitory activity in previous research. Here, we evaluated the fermentation characteristics (pH, titratable acidity, free amino nitrogen, and viable bacterial counts), ACE-inhibitory activity, and contents of Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) peptides of stored yogurt (4°C for 28 d) fermented by L. helveticus isolate H9 (initially inoculated at 4 concentrations), from cow, mare, and soy milks. During storage, the pH and titratable acidity remained stable in yogurts produced from all milk types and all inoculation concentrations. The viable bacterial counts in all stored yogurts ranged between 10(6.72) and 10(8.59) cfu/g. The highest ACE-inhibitory activity (70.9-74.5%) was achieved at inoculation concentrations of 5×10(6) cfu/mL. The ACE-inhibitory tripeptides VPP and IPP as determined by ultra-performance liquid chromatography-tandem mass spectrometry were not produced in yogurt made from soy milk or mare milk. These evaluations indicate that L. helveticus H9 has good probiotic properties and would be a promising candidate for production of fermented food with probiotic properties.
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Affiliation(s)
- Jicheng Wang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China
| | - Changkun Li
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China
| | - Jiangang Xue
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China
| | - Jie Yang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China
| | - Qing Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China
| | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China; Synergetic Innovation Center of Food Safety and Nutrition, Jiang Nan University, Wuxi, Jiang Su 214122, China
| | - Yongfu Chen
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, P.R.C. Synergetic Innovation Center of Food Safety and Nutrition, Hohhot 010018, China; Synergetic Innovation Center of Food Safety and Nutrition, Jiang Nan University, Wuxi, Jiang Su 214122, China.
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Børsting MW, Stallknecht MK, Vogensen FK, Ardö Y. Influence of proteolytic Lactococcus lactis subsp. cremoris on ripening of reduced-fat Cheddar cheese made with camel chymosin. Int Dairy J 2015. [DOI: 10.1016/j.idairyj.2014.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Børsting M, Qvist K, Brockmann E, Vindeløv J, Pedersen T, Vogensen F, Ardö Y. Classification of Lactococcus lactis cell envelope proteinase based on gene sequencing, peptides formed after hydrolysis of milk, and computer modeling. J Dairy Sci 2015; 98:68-77. [DOI: 10.3168/jds.2014-8517] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/02/2014] [Indexed: 11/19/2022]
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11
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Characterization of the mature cell surface proteinase of Lactobacillus delbrueckii subsp. lactis CRL 581. Appl Microbiol Biotechnol 2014; 99:4277-86. [PMID: 25487890 DOI: 10.1007/s00253-014-6258-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 11/18/2014] [Accepted: 11/20/2014] [Indexed: 10/24/2022]
Abstract
The cell envelope-associated proteinase (CEP) of Lactobacillus delbrueckii subsp. lactis CRL 581 (PrtL) has an essential role in bacterial growth, contributes to the flavor and texture development of fermented products, and can release bioactive health-beneficial peptides during milk fermentation. The genome of L. delbrueckii subsp. lactis CRL 581 possesses only one gene that encodes PrtL, which consists of 1924 amino acids and is a multidomain protein anchored to the cell via its W domain. PrtL was extracted from the cell under high ionic strength conditions using NaCl, suggesting an electrostatic interaction between the proteinase and the cell envelope. The released PrtL was purified and biochemically characterized; its activity was maximal at temperatures between 37 and 40 °C and at pH between 7 and 8. Under optimal conditions, PrtL exhibited higher affinity for succinyl-alanyl-alanyl-prolyl-phenylalanine-p-nitroanilide than for succinyl-alanyl-glutamyl-prolyl-phenylalanine-p-nitroanilide, while methoxy-succinyl-arginyl-prolyl-tyrosyl-p-nitroanilide was not degraded. A similar α- and β-casein degradation pattern was observed with the purified and the cell envelope-bound proteinase. Finally, on the basis of its specificity towards caseins and the unique combination of amino acids at residues thought to be involved in substrate specificity, PrtL can be classified as a representative of a new group of CEP.
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Phelan M, Kerins D. The potential role of milk-derived peptides in cardiovascular disease. Food Funct 2011; 2:153-67. [PMID: 21779574 DOI: 10.1039/c1fo10017c] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bioactive peptides derived from milk proteins are of particular interest to the food industry due to the potential functional and physiological roles that they demonstrate, particularly in relation to cardiovascular disease (CVD). By 2020 it is estimated that heart disease and stroke will become the leading cause of death and disability worldwide. Acute and chronic cardiovascular events may result from alterations in the activity of the renin-angiotensin aldosterone system and activation of the coagulation cascade and of platelets. Medications that inhibit angiotensin converting enzyme (ACE) are widely prescribed in the treatment and prevention of cardiovascular disease. ACE inhibitory peptides are of particular interest due to the presence of encrypted inhibitory peptide sequences. In particular, Ile-Pro-Pro and Val-Pro-Pro are fore runners in ACE inhibition, and have been incorporated into commercial products. Additionally, studies to identify additional novel peptides with similar bio-activity and the ability to withstand digestion during transit through the gastrointestinal tract are ongoing. The potential sources of such peptides in cheese and other dairy products are discussed. Challenges to the bio-availability of such peptides in the gastro intestinal tract are also reviewed. Activation of platelets and the coagulation cascade play a central role in the progression of cardiovascular disease. Platelets from such patients show spontaneous aggregation and an increased sensitivity to agonists which results in vascular damage and endothelial dysfunction associated with CVD. Peptide sequences exhibiting anti-thrombotic activity have been identified from fermented milk products. Studies on such peptides are reviewed and their effects on platelet function are discussed. Finally the ability of food derived peptides to decrease the formation of blood clots (thrombi) is reviewed. In conclusion, due to the widespread nature of cardiovascular disease, the identification of food derived compounds that exhibit a beneficial effect in such widespread areas of CVD regulation will have strong clinical potential. Due to the perception that food derived products have an acceptable risk profile they have the potential for widespread acceptance by the public. In this review, selected biological effects relating to CVD are discussed with a view to providing essential information to researchers.
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Affiliation(s)
- Martha Phelan
- Food for Health Ireland, University College Cork, Western Road, Cork, Ireland
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13
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Original features of cell-envelope proteinases of Lactobacillus helveticus. A review. Int J Food Microbiol 2011; 146:1-13. [DOI: 10.1016/j.ijfoodmicro.2011.01.039] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/24/2011] [Accepted: 01/26/2011] [Indexed: 11/23/2022]
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14
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Ndoye B, Lessard MH, LaPointe G, Roy D. Exploring suppression subtractive hybridization (SSH) for discriminating Lactococcus lactis ssp. cremoris SK11 and ATCC 19257 in mixed culture based on the expression of strain-specific genes. J Appl Microbiol 2010; 110:499-512. [DOI: 10.1111/j.1365-2672.2010.04902.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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Pan D, Guo Y. Optimization of sour milk fermentation for the production of ACE-inhibitory peptides and purification of a novel peptide from whey protein hydrolysate. Int Dairy J 2010. [DOI: 10.1016/j.idairyj.2010.01.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Optimisation of hydrolysis conditions for the production of the angiotensin-I converting enzyme (ACE) inhibitory peptides from whey protein using response surface methodology. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.09.041] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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18
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Boutrou R, Kerriou L, Gassi JY. Contribution of Geotrichum candidum to the proteolysis of soft cheese. Int Dairy J 2006. [DOI: 10.1016/j.idairyj.2005.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Broadbent JR, Rodríguez BT, Joseph P, Smith EA, Steele JL. Conversion of Lactococcus lactis cell envelope proteinase specificity by partial allele exchange. J Appl Microbiol 2006; 100:1307-17. [PMID: 16696678 DOI: 10.1111/j.1365-2672.2006.02860.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To determine whether conversion of lactocepin substrate binding regions by gene replacement can alter lactocepin specificity in Lactococcus lactis starter bacteria without affecting other important strain properties. METHODS AND RESULTS We utilized two-step gene replacement to convert substrate-binding determinants in the L. lactis prtP genes encoding group h (bitter) lactocepin in two industrial strains into the corresponding group b (nonbitter) variant. Analysis of lactocepin activity toward alpha(s1)-casein (f 1-23) by reversed-phase high-pressure liquid chromatography demonstrated enzyme specificity among isogenic derivatives had been altered in a manner that was consistent with predicted amino acid substitutions in substrate binding regions. Milk acidification properties of some mutants were not statistically different (P > 0.05) from wild-type parent strains, and strain propensity for autolysis was also not significantly (P > 0.05) changed. CONCLUSIONS Conversion of lactocepin substrate binding regions by allele exchange can effectively alter lactocepin specificity in industrial strains of L. lactis without significantly affecting other important strain properties. SIGNIFICANCE AND IMPACT OF THE STUDY Methodology outlined in this study can be used to alter lactocepin specificity in commercial starter cultures with a propensity for bitter flavour defect, and prtP derivatives developed by this approach should be suitable for commercial application.
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Affiliation(s)
- J R Broadbent
- Western Dairy Center and Department of Nutrition and Food Sciences, Utah State University, Logan, UT, USA
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Sridhar VR, Hughes JE, Welker DL, Broadbent JR, Steele JL. Identification of endopeptidase genes from the genomic sequence of Lactobacillus helveticus CNRZ32 and the role of these genes in hydrolysis of model bitter peptides. Appl Environ Microbiol 2005; 71:3025-32. [PMID: 15932998 PMCID: PMC1151816 DOI: 10.1128/aem.71.6.3025-3032.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes encoding three putative endopeptidases were identified from a draft-quality genome sequence of Lactobacillus helveticus CNRZ32 and designated pepO3, pepF, and pepE2. The ability of cell extracts from Escherichia coli DH5alpha derivatives expressing CNRZ32 endopeptidases PepE, PepE2, PepF, PepO, PepO2, and PepO3 to hydrolyze the model bitter peptides, beta-casein (beta-CN) (f193-209) and alpha(S1)-casein (alpha(S1)-CN) (f1-9), under cheese-ripening conditions (pH 5.1, 4% NaCl, and 10 degrees C) was examined. CNRZ32 PepO3 was determined to be a functional paralog of PepO2 and hydrolyzed both peptides, while PepE and PepF had unique specificities towards alpha(S1)-CN (f1-9) and beta-CN (f193-209), respectively. CNRZ32 PepE2 and PepO did not hydrolyze either peptide under these conditions. To demonstrate the utility of these peptidases in cheese, PepE, PepO2, and PepO3 were expressed in Lactococcus lactis, a common cheese starter, using a high-copy vector pTRKH2 and under the control of the pepO3 promoter. Cell extracts of L. lactis derivatives expressing these peptidases were used to hydrolyze beta-CN (f193-209) and alpha(S1)-CN (f1-9) under cheese-ripening conditions in single-peptide reactions, in a defined peptide mix, and in Cheddar cheese serum. Peptides alpha(S1)-CN (f1-9), alpha(S1)-CN (f1-13), and alpha(S1)-CN (f1-16) were identified from Cheddar cheese serum and included in the defined peptide mix. Our results demonstrate that in all systems examined, PepO2 and PepO3 had the highest activity with beta-CN (f193-209) and alpha(S1)-CN (f1-9). Cheese-derived peptides were observed to affect the activity of some of the enzymes examined, underscoring the importance of incorporating such peptides in model systems. These data indicate that L. helveticus CNRZ32 endopeptidases PepO2 and PepO3 are likely to play a key role in this strain's ability to reduce bitterness in cheese.
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Affiliation(s)
- Vidya R Sridhar
- Department of Food Science, University of Wisconsin--Madison, Madison, WI 53706, USA
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Characteristics of “Tetilla” pasteurized milk cheese manufactured with the addition of autochthonous cultures. Food Microbiol 2004. [DOI: 10.1016/s0740-0020(03)00014-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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23
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Christensen JE, Steele JL. Impaired growth rates in milk of Lactobacillus helveticus peptidase mutants can be overcome by use of amino acid supplements. J Bacteriol 2003; 185:3297-306. [PMID: 12754227 PMCID: PMC155375 DOI: 10.1128/jb.185.11.3297-3306.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To evaluate the contribution of intracellular peptidases to the growth of the 14-amino-acid (aa) auxotroph Lactobacillus helveticus CNRZ32, single- and multiple-peptidase-deletion mutants were constructed. Two broad-specificity aminopeptidases (PepC and PepN) and X-prolyl dipeptidyl aminopeptidase (PepX) were inactivated through successive cycles of chromosomal gene replacement mutagenesis. The inactivation of all three peptidases in JLS247 ((Delta)pepC (Delta)pepN (Delta)pepX) did not affect the growth rate in amino acid-defined medium. However, the peptidase mutants generally had decreased specific growth rates when acquisition of amino acids required hydrolysis of the proteins in milk, the most significant result being a 73% increase in generation time for JLS247. The growth rate deficiencies in milk were overcome by amino acid supplements with some specificity to each of the peptidase mutants. For example, milk supplementation with Pro resulted in the most significant growth rate increase for (Delta)pepX strains and a 7-aa supplement (Asn, Cys, Ile, Pro, Ser, Thr, and Val) resulted in a JLS247 growth rate indistinguishable from that of the wild type. Our results show that characterization of the activities of the broad-specificity aminopeptidases had little predictive value regarding the amino acid supplements found to enhance the milk growth rates of the peptidase mutant strains. These results represent the first determination of the physiological roles with respect to specific amino acid requirements for peptidase mutants grown in milk.
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Pillidge C, Crow V, Coolbear T, Reid J. Exchanging lactocepin plasmids in lactococcal starters to study bitterness development in Gouda cheese: a preliminary investigation. Int Dairy J 2003. [DOI: 10.1016/s0958-6946(03)00008-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Broadbent JR, Barnes M, Brennand C, Strickland M, Houck K, Johnson ME, Steele JL. Contribution of Lactococcus lactis cell envelope proteinase specificity to peptide accumulation and bitterness in reduced-fat Cheddar cheese. Appl Environ Microbiol 2002; 68:1778-85. [PMID: 11916696 PMCID: PMC123837 DOI: 10.1128/aem.68.4.1778-1785.2002] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bitterness is a flavor defect in Cheddar cheese that limits consumer acceptance, and specificity of the Lactococcus lactis extracellular proteinase (lactocepin) is widely believed to be a key factor in the development of bitter cheese. To better define the contribution of this enzyme to bitterness, we investigated peptide accumulation and bitterness in 50% reduced-fat Cheddar cheese manufactured with single isogenic strains of Lactococcus lactis as the only starter. Four isogens were developed for the study; one was lactocepin negative, and the others produced a lactocepin with group a, e, or h specificity. Analysis of cheese aqueous extracts by reversed-phase high-pressure liquid chromatography confirmed that accumulation of alpha(S1)-casein (f 1-23)-derived peptides f 1-9, f 1-13, f 1-16, and f 1-17 in cheese was directly influenced by lactocepin specificity. Trained sensory panelists demonstrated that Cheddar cheese made with isogenic starters that produced group a, e, or h lactocepin was significantly more bitter than cheese made with a proteinase-negative isogen and that propensity for bitterness was highest in cells that produced group h lactocepin. These results confirm the role of starter proteinase in bitterness and suggest that the propensity of some industrial strains for production of the bitter flavor defect in cheese could be altered by proteinase gene exchange or gene replacement.
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Affiliation(s)
- Jeffery R Broadbent
- Western Dairy Center and Department of Nutrition and Food Sciences, Utah State University, Logan, Utah 84322-8700, USA.
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Exterkate FA, Slangen C, Siezen RJ. Effect of genetically modified Lactococcus lactis cell-envelope proteinases with altered specificity on the course of casein degradation under cheese conditions. Int Dairy J 2001. [DOI: 10.1016/s0958-6946(01)00065-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fernandez-Espla MD, Garault P, Monnet V, Rul F. Streptococcus thermophilus cell wall-anchored proteinase: release, purification, and biochemical and genetic characterization. Appl Environ Microbiol 2000; 66:4772-8. [PMID: 11055922 PMCID: PMC92378 DOI: 10.1128/aem.66.11.4772-4778.2000] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2000] [Accepted: 08/04/2000] [Indexed: 02/06/2023] Open
Abstract
Streptococcus thermophilus CNRZ 385 expresses a cell envelope proteinase (PrtS), which is characterized in the present work, both at the biochemical and genetic levels. Since PrtS is resistant to most classical methods of extraction from the cell envelopes, we developed a three-step process based on loosening of the cell wall by cultivation of the cells in the presence of glycine (20 mM), mechanical disruption (with alumina powder), and enzymatic treatment (lysozyme). The pure enzyme is a serine proteinase highly activated by Ca(2+) ions. Its activity was optimal at 37 degrees C and pH 7.5 with acetyl-Ala-Ala-Pro-Phe-paranitroanilide as substrate. The study of the hydrolysis of the chromogenic and casein substrates indicated that PrtS presented an intermediate specificity between the most divergent types of cell envelope proteinases from lactococci, known as the PI and PIII types. This result was confirmed by the sequence determination of the regions involved in substrate specificity, which were a mix between those of PI and PIII types, and also had unique residues. Sequence analysis of the PrtS encoding gene revealed that PrtS is a member of the subtilase family. It is a multidomain protein which is maturated and tightly anchored to the cell wall via a mechanism involving an LPXTG motif. PrtS bears similarities to cell envelope proteinases from pyogenic streptococci (C5a peptidase and cell surface proteinase) and lactic acid bacteria (PrtP, PrtH, and PrtB). The highest homologies were found with streptococcal proteinases which lack, as PrtS, one domain (the B domain) present in cell envelope proteinases from all other lactic acid bacteria.
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Affiliation(s)
- M D Fernandez-Espla
- Unité de Recherche de Biochimie et Structure des Protéines, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France
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Bruinenberg PG, De Vos WM, Siezen RJ. Deletion of various carboxy-terminal domains of Lactococcus lactis SK11 proteinase: effects on activity, specificity, and stability of the truncated enzyme. Appl Environ Microbiol 2000; 66:2859-65. [PMID: 10877779 PMCID: PMC92084 DOI: 10.1128/aem.66.7.2859-2865.2000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Lactococcus lactis SK11 cell envelope proteinase is an extracellular, multidomain protein of nearly 2,000 residues consisting of an N-terminal serine protease domain, followed by various other domains of largely unknown function. Using a strategy of deletion mutagenesis, we have analyzed the function of several C-terminal domains of the SK11 proteinase which are absent in cell envelope proteinases of other lactic acid bacteria. The various deletion mutants were functionally expressed in L. lactis and analyzed for enzyme stability, activity, (auto)processing, and specificity toward several substrates. C-terminal deletions of first the cell envelope W (wall) and AN (anchor) domains and then the H (helix) domain leads to fully active, secreted proteinases of unaltered specificity. Gradually increasing the C-terminal deletion into the so-called B domain leads to increasing instability and autoproteolysis and progressively less proteolytic activity. However, the mutant with the largest deletion (838 residues) from the C terminus and lacking the entire B domain still retains proteolytic activity. All truncated enzymes show unaltered proteolytic specificity toward various substrates. This suggests that the main role played by these domains is providing stability or protection from autoproteolysis (B domain), spacing away from the cell (H domain), and anchoring to the cell envelope (W and AN domains). In addition, this study allowed us to more precisely map the main C-terminal autoprocessing site of the SK11 proteinase and the epitope for binding of group IV monoclonal antibodies.
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Exterkate FA. Structural changes and interactions involved in the Ca(2+)-triggered stabilization of the cell-bound cell envelope proteinase in Lactococcus lactis subsp. cremoris SK11. Appl Environ Microbiol 2000; 66:2021-8. [PMID: 10788376 PMCID: PMC101449 DOI: 10.1128/aem.66.5.2021-2028.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell-bound cell envelope proteinase (CEP) of the mesophilic cheese-starter organism Lactococcus lactis subsp. cremoris SK11 is protected from rapid thermal inactivation at 25 degrees C by calcium bound to weak binding sites. The interactions with calcium are believed to trigger reversible structural rearrangements which are coupled with changes in specific activity (F. A. Exterkate and A. C. Alting, Appl. Env. Microbiol. 65:1390-1396, 1999). In order to determine the significance of the rearrangements for CEP stability and the nature of the interactions involved, the effects of the net charge present on the enzyme and of different neutral salts were studied with the stable Ca-loaded CEP, the unstable so-called "Ca-free" CEP and with the Ca-free CEP which was stabilized nonspecifically and essentially in its native conformation by the nonionic additive sucrose. The results suggest that strengthening of hydrophobic interactions is conducive to stabilization of the Ca-free CEP. On the other hand, a hydrophobic effect contributes significantly to the stability of the Ca-loaded CEP; a phased salting-in effect by a chaotropic salt suggests a complex inactivation process of this enzyme due to weakening of hydrophobic interactions and involving an intermediate enzyme species. Moreover, a Ca-triggered increase of a relatively significant hydrophobic effect in the sucrose-stabilized Ca-free CEP occurs. It is suggested that in the Ca-free CEP the absence of both local calcium-mediated backbone rigidification and neutralization of negative electrostatic potentials in the weak Ca-binding sites, and in addition the lack of significant hydrophobic stabilization, increase the relative effectiveness of electrostatic repulsive forces on the protein to an extent that causes the observed instability. The conditions in cheese seem to confer stability upon the cell-bound enzyme; its possible involvement in proteolysis throughout the ripening period is discussed.
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Affiliation(s)
- F A Exterkate
- Department of Flavour and Natural Ingredients, NIZO Food Research, 6710 BA Ede, The Netherlands.
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Specificity of lactococcus lactis subsp. cremoris SK11 proteinase, lactocepin III, in low-water-activity, high-salt-concentration humectant systems and its stability compared with that of lactocepin I. Appl Environ Microbiol 1999; 65:2947-53. [PMID: 10388688 PMCID: PMC91441 DOI: 10.1128/aem.65.7.2947-2953.1999] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Marked changes in the specificity of hydrolysis of alphas1-, beta-, and kappa-caseins by lactocepin III from Lactococcus lactis subsp. cremoris SK11 were found in humectant systems giving the equivalent water activity (aw) and salt concentration of cheddar cheese. Correlations were noted between certain peptides produced by the activity of lactocepin III in the humectant systems and peptides found in cheddar cheese. The stability of lactocepin III was compared with that of lactocepin I from L. lactis subsp. cremoris HP in the humectant systems at different pHs. Significant differences between the stability of each of the lactocepin types were evident. The relationship between stability and humectant type, aw, pH, and NaCl concentration was complex. Nevertheless, in those systems where aw, pH, and NaCl concentration were equivalent to those in cheddar cheese, lactocepin I was generally more stable than lactocepin III. It was concluded that differences in the specificity and/or stability of various lactocepin types are likely to persist in cheese itself and therefore potentially contribute to differences in the peptide composition of ripened cheese.
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Exterkate FA, Alting AC. Role of calcium in activity and stability of the Lactococcus lactis cell envelope proteinase. Appl Environ Microbiol 1999; 65:1390-6. [PMID: 10103227 PMCID: PMC91197 DOI: 10.1128/aem.65.4.1390-1396.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mature lactococcal cell envelope proteinase (CEP) consists of an N-terminal subtilisin-like proteinase domain and a large C-terminal extension of unknown function whose far end anchors the molecule in the cell envelope. Different types of CEP can be distinguished on the basis of specificity and amino acid sequence. Removal of weakly bound Ca2+ from the native cell-bound CEP of Lactococcus lactis SK11 (type III specificity) is coupled with a significant reversible decrease in specific activity and a dramatic reversible reduction in thermal stability, as a result of which no activity at 25 degrees C (pH 6.5) can be measured. The consequences of Ca2+ removal are less dramatic for the CEP of strain Wg2 (mixed type I-type III specificity). Autoproteolytic release of CEP from cells concerns this so-called "Ca-free" form only and occurs most efficiently in the case of the Wg2 CEP. The results of a study of the relationship between the Ca2+ concentration and the stability and activity of the cell-bound SK11 CEP at 25 degrees C suggested that binding of at least two Ca2+ ions occurred. Similar studies performed with hybrid CEPs constructed from SK11 and Wg2 wild-type CEPs revealed that the C-terminal extension plays a determinative role with respect to the ultimate distinct Ca2+ dependence of the cell-bound CEP. The results are discussed in terms of predicted Ca2+ binding sites in the subtilisin-like proteinase domain and Ca-triggered structural rearrangements that influence both the conformational stability of the enzyme and the effectiveness of the catalytic site. We argue that distinctive primary folding of the proteinase domain is guided and maintained by the large C-terminal extension.
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Affiliation(s)
- F A Exterkate
- Department of Biophysical Chemistry, Netherlands Institute for Dairy Research (NIZO), 6710 BA Ede, The Netherlands.
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Broadbent JR, Strickland M, Weimer BC, Johnson ME, Steele JL. Peptide Accumulation and Bitterness in Cheddar Cheese Made Using Single-Strain Lactococcus lactis Starters with Distinct Proteinase Specificities. J Dairy Sci 1998. [DOI: 10.3168/jds.s0022-0302(98)75581-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Palencia PF, Peláez C, Martín-Hernández M. Specificity of the bound and free forms of the cell-envelope proteinase of Lactobacillus casei subsp. casei IFPL 731 towards the ?s1-casein-(1?23)-fragment. Lett Appl Microbiol 1997. [DOI: 10.1111/j.1472-765x.1997.tb00002.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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