Enhancing the Survival of Lactobacillus acidophilus in Acidophilus Milk by Incorporating Maranta arundinacea (Arrowroot) Extract

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Date
2013
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Uva Wellassa University of Sri Lanka
Abstract
Acidophilus milk is a traditional fermented beverage produced using Lactobacillus acidophilus as the starter culture. It has a mild sour taste (Amiri et al., 2010). Lactobacillus acidophilus is one of the probiotic bacteria used in the food industry. The potential health benefits associated with fermented products containing Lactobacillus acidophilus as dietary adjuncts are improved digestion of lactose, control of serum cholesterol, antagonistic action towards pathogens and control of certain intestinal cancers (Maria, 2007; Lampert, 1975). To produce desired benefits, there should be minimum of 10 -10 CFU of probiotic bacteria /gram or mL of product at the time of consumption (Lourens-Hattingh et al., 2001). However, many studies have shown that the number of viable Lactobacillus acidophilus colonies decline with the storage time. This is one of the major limitations faced in the functional food industry. Incorporation of prebiotics such as fructooligosaccharide (FOS) can be used to enhance the survival of probiotic bacteria (Gibson and Roberfroid, 1995). Arrowroot (Maranta arundinacea) is a locally available rhizomatous herbaceous plant which contains 29.1 mg/g of fructooligosaccharides Kaligayahan, 2009). Therefore, the extract of Arrowroot rhizomes may be used to enhance the survival of probiotic bacteria in dairy products. The objective of this study was to assess the effect of water soluble extract of Arrowroot on the survival of Lactobacillus acidophilus in acidophilus milk during refrigerated conditions. This study was conducted at Uva Wellassa University, Badulla, Sri Lanka. Matured arrowroot rhizomes were collected from home gardens of Badulla District. Within a day of harvest, yams were thoroughly washed with running water and cut into cubes (20-30 g). According to Maria et C. Arrowroot samples were grounded with water (1:2) at 27 C in to a pulp. One sample was continuously stirred (100 rpm) for 20 minutes under 40 C and the other sample was maintained under 70 C for another 20 minutes. Then, they were filtered through three layered cheese cloth to remove suspended particles to obtain a clear extract. Similar to Ogunlakin et al. (2012), arrowroot powder was prepared by oven dry method using cleaned and washed Arrowroot cubes at 70°C for 4 hours. Then, they were ground into a powder and sieved. The acidophilus milk was prepared using the method of Yildiz (2010) with some modifications. Standardized cow milk (fat 2.5 %, SNF 8.25%) was used to prepare acidophilus milk. Probiotic culture was prepared using a freeze dried lactic culture (La-5 , Chr. Hansen, Denmark) which contained Lactobacillus acidophilus strain LA-5. There were five treatments according to the type of prebiotics; acidophilus milk with 3% (w/v) powdered Arrowroot rhizomes (T1), acidophilus milk with 45% (v/v) Arrowroot extract (extracted at 70 C) (T2), acidophilus milk with 45% (v/v) of Arrowroot extract (extracted at 40 C) (T3), 2% (w/v) of inulin (Raftilose Sigma Aldrich, USA) (T4) and the control sample without any prebiotics. The best incorporation levels of prebiotics without affecting sensory properties of acidophilus milk were identified by preliminary trials. Arrowroot extract and inulin incorporated cow milk were heated to 95 C for 8 minutes separately. Then they were cooled to 43 C and inoculated with 10% (w/v) LA-5 probiotic culture which contains Lactobacillus acidophilus.
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Keywords
Animal Sciences, Food Science, Food Technology, Milk, Milk Production
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