قابليت تخمير و فعاليت پروتئوليتيكي لاكتيك اسيد باكتري‌ها در شير و مقايسه فعاليت ضدقارچي لاكتيك اسيد باكتري‌ها در شير پس چرخ و MRS مايع

Fermentation Capability an‎d Proteolytic Activity of Lactic Acid Bacteria in Milk and Comparison of Antifungal Activity of Lactic Acid Bacteria in Skim Milk and MRS

در اﯾﻦ ﺗﺤﻘﯿﻖ،ﻗﺎﺑﻠﯿﺖ ﺗﺨﻤﯿﺮﺷﻮﻧﺪﮔﯽ ﺷﯿﺮ ﺗﻮﺳﻂ6 ﺟﺪاﯾﻪ از ﻻﮐﺘﯿﮏ اﺳﯿﺪ ﺑﺎﮐﺘﺮيﻫﺎ، ﻓﻌﺎﻟﯿﺖ ﭘﺮوﺗﺌﻮﻟﯿﺘﯿﮑﯽ ﻻﮐﺘﯿﮏ اﺳﯿﺪ ﺑﺎﮐﺘﺮيﻫﺎ در ﺷﯿﺮﺑﺎ ﻣﻌﺮف اورﺗﻮ ﻓﺘﺎل دي آﻟﺪﻫﯿﺪ )OPA(و ﺧﺎﺻﯿﺖ ﺿﺪﻗﺎرﭼﯽ ﻻﮐﺘﯿﮏ اﺳﯿﺪ ﺑﺎﮐﺘﺮيﻫﺎ درMRS ﻣﺎﯾﻊ و ﺷﯿﺮ ﭘﺲ ﭼﺮخ در ﻣﻘﺎﺑﻞ آﺳﭙﺮژﯾﻠﻮس ﻓﻼوس و ﮐﺎﻧﺪﯾﺪا آﻟﺒﯿﮑﻨﺴﻤﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. از ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﺑﺮوﯾﺲKMJC1، ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس اﺳﯿﺪي ﭘﯿﺴﯿﺲKMJC2، ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﮐﻮرواﺗﻮسKMJC3 و ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﭘﻼﻧﺘﺎرومKMJC4 ﺟﺪا ﺷﺪه از ﭘﻨﯿﺮ ﮐﻮزه، ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﻫﻠﻮﺗﯿﮑﻮسKMCH1 ﺟﺪا ﺷﺪه از دوغ ﺷﺘﺮ )ﭼﺎل( و ﻻﮐﺘﻮﮐﻮﮐﻮس ﻻﮐﺘﯿﺲ KMCM3 ﺟﺪا ﺷﺪه از ﺷﯿﺮ ﺷﺘﺮ اﺳﺘﻔﺎده ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ در ﻣﯿﺎن ﺟﺪاﯾﻪﻫﺎ ،ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﭘﻼﻧﺘﺎرومKMJC4 ﭘﺲ از 48 ﺳﺎﻋﺖ، ﻻﮐﺘﻮﮐﻮﮐﻮس ﻻﮐﺘﯿﺲ KMCM3 ﭘﺲ از 16 ﺳﺎﻋﺖ و ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﻫﻠﻮﺗﯿﮑﻮسKMCH1 ﭘﺲ از60 ﺳﺎﻋﺘﺎز ﻗﺎﺑﻠﯿﺖ ﺗﺨﻤﯿﺮﺷﻮﻧﺪﮔﯽ ﺷﯿﺮ ﺑﺮﺧﻮردار ﺑﻮدﻧﺪ. ﺳﻨﺠﺶ ﻣﯿﺰان ﭘﺮوﺗﺌﻮﻟﯿﺰ اﻧﺠﺎم ﺷﺪه در ﺷﯿﺮﻫﺎي ﺗﺨﻤﯿﺮي ﺗﻮﺳﻂ ﺟﺪاﯾﻪﻫﺎي ﻣﺬﮐﻮر ﺑﺎ اﺳﺘﻔﺎده از ﻣﻌﺮف OPA ﻧﺸﺎن داد ﻓﻌﺎﻟﯿﺖ ﭘﺮوﺗﺌﻮﻟﯿﺘﯿﮑﯽ ﻣﺮﺑﻮط ﺑﻪ ﺟﺪاﯾﻪﻫﺎي ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﻫﻠﻮﺗﯿﮑﻮسKMCH1، ﻻﮐﺘﻮﮐﻮﮐﻮس ﻻﮐﺘﯿﺲKMCM3 و ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﭘﻼﻧﺘﺎرومKMJC4 ﺑﻪ ﺗﺮﺗﯿﺐ mg/ml 0/34 ، 0/26 و 0/22 ﺑﻮد. در ﺑﺮرﺳﯽ اﺛﺮ ﺿﺪﻗﺎرﭼﯽ روﻣﺎﻧﺪ ﺣﺎﺻﻞ از ﻓﻌﺎﻟﯿﺖ ﺟﺪاﯾﻪﻫﺎي ﻻﮐﺘﯿﮑﯽ ﻣﺸﺨﺺ ﺷﺪ روﻣﺎﻧﺪ ﺣﺎﺻﻞ از ﮐﺸﺖ در MRS ﻣﺎﯾﻊ اﺛﺮ ﺑﺎزدارﻧﺪﮔﯽ ﺑﯿﺸﺘﺮي )mg/ml 50 و 25=MIC( ﻧﺴﺒﺖ ﺑﻪ روﻣﺎﻧﺪ ﺣﺎﺻﻞ از ﮐﺸﺖ در ﺷﯿﺮ ﭘﺲ ﭼﺮﺧﺪاﺷﺖ،ﺑﻪ ﻃﻮري ﮐﻪ MIC ﺑﺮاي روﻣﺎﻧﺪ ﺣﺎﺻﻞ از ﺷﯿﺮ ﺗﺨﻤﯿﺮي ﻣﺸﺎﻫﺪه ﻧﺸﺪ. در ﭘﺎﯾﺎﻧﻤﯽﺗﻮان ﻧﺘﯿﺠﻪ ﮔﺮﻓﺖ ﮐﻪ ﻻﮐﺘﻮﮐﻮﮐﻮس ﻻﮐﺘﯿﺲKMCM3 در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺟﺪاﯾﻪﻫﺎي دﯾﮕﺮ در زﻣﺎن ﮐﻮﺗﺎهﺗﺮي)16 ﺳﺎﻋﺖ( ﺗﻮاﻧﺴﺖ ﻻﮐﺘﻮز ﺷﯿﺮ را ﺗﺨﻤﯿﺮ ﮐﻨﺪ. ﺑﯿﺸﺘﺮﯾﻦ ﻓﻌﺎﻟﯿﺖ ﭘﺮوﺗﺌﻮﻟﯿﺘﯿﮑﯽ ﺗﻮﺳﻂ ﺟﺪاﯾﻪﻫﺎي ﻣﺬﮐﻮر در ﺷﯿﺮ، ﻣﺮﺑﻮط ﺑﻪ ﺟﺪاﯾﻪ ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﻫﻠﻮﺗﯿﮑﻮسmg/ml)KMCH1 0/34( ﺑﻮد.ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﭘﻼﻧﺘﺎرومKMJC4 ﺟﺪاﺷﺪه از ﭘﻨﯿﺮﮐﻮزه ﺑﻪﻋﻨﻮان ﺑﻬﺘﺮﯾﻦ ﺟﺪاﯾﻪ ﺑﺮاي ﺗﻬﯿﻪ روﻣﺎﻧﺪ ﺣﺎﺻﻞ از MRS ﻣﺎﯾﻊ ﺑﺎ ﺧﺎﺻﯿﺖ ﺿﺪ ﻗــﺎرﭼــﯽ ﺑﻮد.

In this study, milk fermentation capability by 6 isolates of lactic acid bacteria, proteolytic activity of lactic acid bacteria in milkby ortho-phthaldialdehyde (OPA)reagentand antifungal property of lactic acid bacteria in MRS broth and skim milk against Aspergillus flavus and Candida albicanswere studied. L. brevis KMJC1, L. acidipiscis KMJC2, L. curvatus KMJC3 and L. plantarum KMJC4 isolated from Jug cheese, L. helveticus KMCH1 isolated from camel doogh (Chal) and Lac. lactis KMCM3 isolated from camel milk were used. The results showed thatamong the isolates,L. plantarum KMJC4after 48 h, Lac. lactis KMCM3 after 16 hand L. helveticus KMCH1 after 60 hhad milk fermentation capability. The measurement of proteolysis rate performed infermented milk by mentioned isolates using OPA reagent indicated that the proteolytic activity of L. helveticus KMCH1, Lac. lactis KMCM3 and L. plantarum KMJC4 were 0.34, 0.26 and 0.22 mg/ml, respectively. In study of the antifungal effect of supernatant resulting from the activity of lactic isolates, it was found that supernatant obtained from culture in MRS broth had a more inhibitory effect (MIC= 25 and 50 mg/ml) than the supernatant obtained from the culture in the skim milk, as the MIC was not observed for the supernatant obtained from fermented milk. In the end, it can be concluded that Lac. lactis KMCM3 was able to ferment lactose in milk in comparisonwith other isolates in shorter time (16 h). The highest proteolytic activity of the isolates in milk was related to the isolate of L. helveticus KMCH1 (0.34 mg/ml). L. plantarum KMJC4 isolated from Jug cheese was as the best isolate for the preparation of supernatant resulting from MRS broth with the antifungal property.