D. Maheswara Reddy A. Jagadeesh Babu B. Eswara Rao S. Moorthy S. Vani Vol 7(4), 250-255 DOI- http://dx.doi.org/10.5455/ijlr.20170324030617
The present study was intended to evaluate the microbiological quality and shelf life of chicken meat sausages incorporated with natural antioxidant extracts i.e., rosemary (Rosmarinus officinalis) and green tea (Camellia sinensis) each at 0.2 % level and compare with synthetic antioxidant (BHA at 0.01% level) under refrigeration (4±1°c) for a period of 8 days. Microbiological quality evaluation revealed that chicken meat sausages incorporated with green tea extract at 0.2 % level had significantly (P<0.05) lower standard plate count and coliform count during refrigerated storage as compared to control and other treatments. Psychrotrophs and yeast and moulds could not be detected in any of the samples during refrigerated storage. Considering the results obtained in the study, it may be concluded that addition of green tea extract at 0.2 % level protect the chicken meat sausages against microbial attack more effectively than 0.2 % rosemary extract and synthetic antioxidants.
Keywords : Chicken Meat Sausages Green Tea Extract Rosemary Extract BHA Microbial Studies
Introduction
Meat is highly perishable food. Hence, utmost care should be taken during processing and storage till its consumption. The shelf life of fresh meat products depend upon microbial load and chemical changes. Presence of high microbial count and an increase in bacterial number during storage is a sign of spoilage. Recently there has been an increasing interest in discovering new natural antimicrobial substances to preserve meat and meat products. Natural antioxidants include a range of natural products from plants or animals which can be used to improve the keeping quality of foods, reduce or eliminate the pathogenic microorganisms and improve the overall quality of foods. Attention has focused on health problems associated with microbial contamination in food, and consumers are looking for microbiological safe meat products and those preserved with natural substances than synthetics. Similarly the meat industry is looking for natural solutions to lower microbial spoilage and extend the shelf-life of meat products than synthetic additives. The synthetic antioxidants have negative health effects. Due to concerns about toxicological effects of synthetic antioxidants, naturally derived antioxidants are better and safer than synthetics. The antimicrobial activity of extracts from leaves, grains, oil seeds, spices are being used since a long time. Green tea leaf extract and rosemary extract are important as a functional food in the diet because of their high poly phenol contents. The active anti oxidant and antimicrobial compounds of green tea and rosemary extracts promote health by preventing lipid oxidation and providing antibacterial, anti-carcinogenic and antiviral ability (Yang et al., 2000). The strong free-radical-scavenging ability, antimicrobial activity and the iron-chelating effects of these two natural antioxidants offer a possible mechanism for the antioxidant and antimicrobial effects. Hence the current research was designed to study the microbial quality of value added chicken meat sausages with natural and synthetic antioxidants during refrigerated storage.
Materials and Methods
Preparation of Sausages
The deboned chicken meat was procured from local retail outlet and remaining non meat ingredients was purchased from local market of Tirupati. Formulation for preparation of sausages has given in Table 1 and preparation of sausages has been outlined in Fig.1.
Table 1: Formulations of chicken meat sausages incorporated with various levels of antioxidants
Ingredients (gm per cent) | Control | Rosemary Extract | Green Tea Extract | BHA |
Chicken meat | 68 | 67.8 | 67.8 | 67.99 |
Oat flour | 9 | 9 | 9 | 9 |
Poly-phosphates | 0.5 | 0.5 | 0.5 | 0.5 |
Sugar | 1 | 1 | 1 | 1 |
Salt | 1.5 | 1.5 | 1.5 | 1.5 |
Spice mix | 2 | 2 | 2 | 2 |
Condiment mix | 5 | 5 | 5 | 5 |
Vegetable oil | 6 | 6 | 6 | 6 |
Chilled water | 7 | 7 | 7 | 7 |
Rosemary extract | – | 0.2 | – | – |
Green tea extract | – | – | 0.2 | – |
BHA | – | – | – | 0.01 |
Total | 100 | 100 | 100 | 100 |
Fig.1: Flow chart for the preparation of chicken meat sausages incorporated with various levels of antioxidants
Broiler birds were procured from local market and dressed hygienically
Deboned manually
Meat diced to small chunks of 1 inch cubes
Mincing of meat
Addition of phosphates, salt, sugar to minced meat and chopping for 30 seconds
Addition of spice mix and condiment mix and chopping for 45 seconds
Addition of vegetable oil and chopping for 30 seconds
Addition of oat flour at 9 %
Mix ice water while chopping and chop it for 20 sec
Addition of antioxidants in separate batches
Natural antioxidants Synthetic antioxidant
Rosemary extract Green tea extract Butylated hydroxyanisole
0.2 per cent 0.2 per cent 0.01per cent
Mincing
Emulsion
Stuffed into synthetic cellulose casings (SCC21) using horizontal sausage stuffer linking at uniform interval
Cooking in open bath cooker for 25 min until internal core temperature reaches to 80ºC
Packed in polyethylene bags separately
Storage
Refrigeration (4±1°C)
Analysis
(0-8 days at 2 days interval)
Analytical Parameters
The mesophilic, the psychrophilic and the yeast and mould counts per gram of chicken meat sausages at refrigerated (4±1°C) temperature were estimated as per the techniques recommended by Chestnut et al. (1977). For coliform estimation Mac Conkey agar was prepared and 1ml of inoculum of each dilution was placed in duplicate petridishes. The sterile molten and cooled (45 ºC) medium was poured in 15-20 ml quantities into each petridish and mixed thoroughly. The petridishes after solidification of the medium were incubated at 37 ºC for 18-24 hrs. Pink colored colonies were counted and expressed as log10 cfu/g of sample. The data thus obtained was subjected to statistical analysis using SPSS MAC, version 20.0, SPSS Chicago (US).
Results and Discussion
Standard Plate Count
Among the treatments chicken meat sausages incorporated with green tea extract at 0.2% showed significantly (P<0.05) lower counts than the other treatments which might be due to the presence of polyphenolic catechins like epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate which causes irreversible damage to bacterial cytoplasmic membrane and check the microbial growth (Hara 2001). They also inhibit bacterial growth and protease activity by damaging the cell wall and cytoplasm, causing rapid structural destruction (Cowan, 1999). These results were in accordance with Lorenzo et al., 2014 in pork patties, Jamwal et al., 2015 in chicken patties, and Zhang et al., 2016 in raw chicken meat. The overall mean bacterial count (log10 cfu/g) increased significantly (P<0.05) with increase in storage period during refrigeration. This might be due to the suitable temperature and relative availability of moisture and nutrients for the growth of mesophilic bacteria. These results were in accordance with Szymanczuk et al. (2011) in refrigerated pork batters and Reddy et al. (2017) in chicken meat patties.
Coliforms
The analysis of variance revealed that chicken meat sausages incorporated with green tea extract at 0.2% showed significantly (P<0.05) lower counts than the other treatments which might be due to the presence of polyphenolic catechins like epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate which causes irreversible damage to bacterial cytoplasmic membrane and check the microbial growth (Hara 2001). These results were in accordance with Rounds et al. (2012) in cooked beef patties, and Reddy et al. (2017) in chicken meat patties. The overall mean coliform count (log6 cfu/g) increased significantly (P<0.05) with increase in storage period during refrigeration. This might be due to the permissive temperature and relative availability of moisture and nutrients for the growth of coliform bacteria. These results were in accordance with Szymanczuk et al. (2011) in refrigerated pork batters and Reddy et al. (2017) in chicken meat patties.
Psychrophiles
Psychrophiles could not be detected in any of the treatments and control during refrigerated storage. This might be due to the temperature variance for growth of psychrophilic bacteria. The results were in agreement with and Reddy et al. (2017) in chicken meat patties.
Yeast and Mold Count
Yeast and moulds could not be detected in any of the treatments in the present study. This might be due to hygienic processing of practices and also might be attributed to the antifungal effect of added spices (Pandey et al., 2013). The results were in agreement with Reddy et al. (2017) in chicken meat patties.
Table 2: Standard plate count (log10cfu/g) values of chicken meat sausages as influenced by different treatments during refrigerated storage (4±1°C)
Days of Storage | Control | Treatments | ||
T1 (0.2 % Rosemary) | T2 (0.2 % Green Tea) | T3 (0.01% BHA) | ||
0 | 4.63±0.01Ca | 4.20±0.01Bc | 4.09±0.01Ac | 4.56±0.01Cb |
2 | 5.22±0.01Db | 3.64±0.01Ba | 3.20±0.01Aa | 4.12±0.01Ca |
4 | 5.49±0.01Cc | 3.82±0.01Ab | 3.71±0.01Ab | 4.43±0.01Bb |
6 | 5.82±0.01Dd | 4.25±0.01Bc | 4.05±0.01Ac | 4.79±0.01Cc |
8 | 6.93±0.01De | 4.75±0.01Bd | 4.55±0.01Ad | 5.90±0.01Cd |
(P<0.05); Means bearing at least one common superscript in the same row and in the same column do not differ significantly; Capital alphabet superscripts are used to show the significance difference for rows; Small alphabet superscripts are used to show the significance difference for columns
Table 3: Coliform count (log10cfu/g) values of chicken meat sausages as influenced by different treatments during refrigerated storage (4±1°C)
Days of Storage | Control | Treatments | ||
T1 (0.2 % Rosemary) | T2 (0.2 % Green Tea) | T3 (0.01% BHA) | ||
0 | 2.24±0.07Ca | 2.15±0.01Bc | 2.05±0.03Ac | 2.17±0.01Ba |
2 | 6.20±0.03Db | 1.90±0.02Ba | 1.15±0.01Aa | 2.84±0.02Cb |
4 | 8.02±0.02Cc | 1.98±0.01Ab | 1.84±0.02Ab | 3.21±0.02Bc |
6 | 8.77±0.01Cd | 3.41±0.02Bd | 2.41±0.03Ad | 3.86±0.05Bd |
8 | 9.61±0.07De | 4.59±0.01Be | 3.58±0.03Ae | 6.17±0.01Ce |
(P<0.05); Means bearing at least one common superscript in the same row and in the same column do not differ significantly; Capital alphabet superscripts are used to show the significance difference for rows; Small alphabet superscripts are used to show the significance difference for columns
Conclusion
Microbiological quality evaluation revealed that chicken meat sausages incorporated with green tea extract at 0.2 % level had significantly (P<0.05) lower standard plate count and coliform count during refrigerated storage as compared to control and other treatments. Thus green tea extracts not only extending the shelf life of the product but also protecting the health of the consumers as compared to control and other treatments during refrigerated storage.
References