بهينه سازي توليد گاما نونا لاكتون توسط لاكتوباسيلوس سانفرانسينسيس در خمير ترش با روش ريز استخراج فاز جامد در فضاي فوقاني

Optimizing Sourdough Processing for the Production of ɣ-nonalactone (Fruity Aroma) by Lactobacillus sanfranciscensis Using Headspace Solid-Phase Microextraction Method

ﺳﺎﺑﻘﻪ و ﻫﺪف: اﺳﺘﻔﺎده از ﺧﻤﯿﺮ ﺗﺮش ﯾﮏ روش ﻣﻨﺎﺳﺐ ﺑﺮاي ﺗﻮﻟﯿﺪ ﻋﻄﺮ و ﻃﻌﻢ ﻃﺒﯿﻌﯽ در ﻧﺎن اﺳﺖ. ﮔﺎﻣﺎﻧﻮﻧﺎﻻﮐﺘﻮن ﯾﮑﯽ از ﺗﺮﮐﯿﺒﺎت ﻓﺮار ﻣﻮﻟﺪ ﻋﻄﺮ ﻣﯿﻮه اي اﺳﺖ. ﻫﺪف ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺑﺮرﺳﯽ ﺗﻮاﻧﺎﯾﯽ ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﺳﺎﻧﻔﺮاﺳﯿﻨﺴﯿﺲ ﺑﺮاي ﺗﻮﻟﯿﺪ ﮔﺎﻣﺎﻧﻮﻧﺎﻻﮐﺘﻮن در ﺧﻤﯿﺮ ﺗﺮش و ﻫﻤﭽﻨﯿﻦ ﺑﺮرﺳﯽ ﺷﺮاﯾﻂ ﺑﻬﯿﻨﻪ ﺑﺮاي ﺗﻮﻟﯿﺪ آن اﺳﺖ. ﻣﻮاد و روشﻫﺎ: در اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮاي ﺗﻬﯿﻪ ﺧﻤﯿﺮ ﺗﺮش از ﻣﺨﻠﻮط آرد ﻫﺎي ﭼﺎودار و ﺟﻮ ﺑﻪ ﻫﻤﺮاه ﺳﺒﻮس ﮔﻨﺪم و ﺳﻮرﺑﯿﺘﻮل اﺳﺘﻔﺎده ﺷﺪ. ﺗﺨﻤﯿﺮ ﺗﻮﺳﻂ ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﺳﺎﻧﻔﺮاﻧﺴﯿﻨﺴﯿﺲ 4332 ATCC اﻧﺠﺎم ﺷﺪ. آزﻣﺎﯾﺶ ﻫﺎ ﺑﺎ روش ﺳﻄﺢ ﭘﺎﺳﺦ ﺑﺎ 5 ﻓﺎﮐﺘﻮر ﻃﺮاﺣﯽ ﺷﺪﻧﺪ ﮐﻪ ﺷﺎﻣﻞ: زﻣﺎن، دﻣﺎ، راﻧﺪﻣﺎن ﺧﻤﯿﺮ، درﺻﺪ ﺳﻮرﺑﯿﺘﻮل و درﺻﺪ ﺳﺒﻮس ﺑﻮد. اﺳﺘﺨﺮاج ﺗﺮﮐﯿﺒﺎت ﻓﺮار ﺧﻤﯿﺮ ﺗﺮش ﺑﺎ روش رﯾﺰ اﺳﺘﺨﺮاج ﻓﺎز ﺟﺎﻣﺪ از ﻓﻀﺎي ﻓﻮﻗﺎﻧﯽ اﻧﺠﺎم ﺷﺪ وﺗﺮﮐﯿﺒﺎت ﻓﺮار اﺳﺘﺨﺮاج ﺷﺪه ﺗﻮﺳﻂ ﮐﺮوﻣﺎﺗﻮﮔﺮاﻓﯽ ﮔﺎزي آﻧﺎﻟﯿﺰ ﺷﺪ. ﯾﺎﻓﺘﻪﻫﺎ: ﺗﺄﺛﯿﺮ ﻫﺮﯾﮏ از ﻋﻮاﻣﻞ ﺑﺮ ﻣﯿﺰان ﺗﻮﻟﯿﺪ ﮔﺎﻣﺎﻧﻮﻧﺎﻻﮐﺘﻮن ﺑﺎ روش ﻃﺮاﺣﯽ ﻣﺮﮐﺐ ﻣﺮﮐﺰي ﻣﺪل ﺳﺎزي ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺧﻤﯿﺮ ﺗﺮش ﺑﺎ اﻓﺰودن 20 % ﺳﺒﻮس ﮔﻨﺪم و 6% ﻗﻨﺪ ﺳﻮرﺑﯿﺘﻮل، ﺑﺎ راﻧﺪﻣﺎن ﺧﻤﯿﺮ 400 ﮐﻪ ﺑﻪ ﻣﺪت 72 ﺳﺎﻋﺖ در دﻣﺎي °C 37 ﺗﺨﻤﯿﺮ ﺷﻮد، ﺑﻬﺘﺮﯾﻦ ﺷﺮاﯾﻂ ﺑﺮاي ﺗﻮﻟﯿﺪ ﮔﺎﻣﺎﻧﻮﻧﺎﻻﮐﺘﻮن اﺳﺖ )26/3ppm(. ﻧﺘﯿﺠﻪ ﮔﯿﺮي: در اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺗﻮاﻧﺎﯾﯽ ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﺳﺎﻧﻔﺮاﺳﯿﻨﺴﯿﺲ ﺑﺮاي ﺗﻮﻟﯿﺪ ﺗﺮﮐﯿﺒﺎت ﻓﺮار ﻣﻄﻠﻮب ﻣﺜﻞ ﮔﺎﻣﺎﻧﻮﻧﺎﻻﮐﺘﻮن ﺑﺎ ﻋﻄﺮ ﻣﯿﻮه اي در ﺧﻤﯿﺮﺗﺮش اﺛﺒﺎت ﺷﺪ. دﺳﺘﺎورد اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﻣﯽ ﺗﻮاﻧﺪ ﻣﻨﺠﺮ ﺑﻪ ﺗﻮﻟﯿﺪ ﻧﺎن ﺣﺎوي ﺧﻤﯿﺮﺗﺮش ﺑﺎ ﻋﻄﺮ ﻣﻄﻠﻮب ﮔﺮدد ﮐﻪ ﻣﻮﺟﺐ ﺗﺸﻮﯾﻖ ﻣﺼﺮف ﮐﻨﻨﺪﮔﺎن ﺑﺮاي ﻣﺼﺮف ﻧﺎن ﺳﺎﻟﻢ ﺣﺎوي ﺧﻤﯿﺮ ﺗﺮش و ﻋﺎري از اﻓﺰودﻧﯽ ﺷﯿﻤﯿﺎﯾﯽ ﻣﯽﮔﺮدد.

Sourdough processing is a well-known method to improve food flavor. One of the most important lactic acid bacteria isolated from sourdoughs is Lactobacillus sanfranciscensis. Because of the bacterial ability for acidification and liberation of the volatile compound precursors, it can strongly affect dough rheology and aromatic properties. In this study, the best conditions for production of ɣ-nonalactone (with fruity aroma) in sourdough were investigated for the first time. Materials & Methods: To prepare sourdough, a mixture of rye and barley flour and wheat bran was used. Fermentation was carried out using Lactobacillus sanfranciscensis ATCC 4332. Experiments were designed using response surface methodology and five factors, including time, temperature, dough yield and sorbitol and bran proportions. Volatiles were extracted from sourdough using headspace solid-phase microextraction method. Extracted volatile compounds were measured using gas chromatograph coupled with a mass selective detector. Results: Effects of independent variables on ɣ-nonalactone production were modeled using central composite design. Experimental data were similar to the predicted data; therefore, results of this model were reliable. Based on the results, fermentation at 37 ºC for 72 h with DY of 400, sorbitol of 6% and 20% of bran provided the most optimum conditions for the production of fruity aroma (26.3 ppm). Conclusion: Investigation of the aromatic profile of sourdough fermented by L. sanfranciscensis showed that this strain was capable of producing desirable aroma during fermentation. Based on the results, time and temperature included strong effects on production of ɣ-nonalactone. In comparison, dough yield did not include significant effects while addition of bran and sorbitol included mild effects.