Z. Muzaffar S. A. Wani F. A. Rather A. H. Sofi M. A. Pal Vol 8(5), 213-219 DOI- http://dx.doi.org/10.5455/ijlr.20170918063209
The present study was conducted with the objective of evaluating the effect of processing method and α-tocopherol on the shelf life stability of feather cum skin meal. The meal was prepared by three different methods viz, hydrothermal, chemical and microbial degradation. α-tocopherol was added to the meal at two levels viz, 400 ppm (T1) and 800 ppm (T2). The meal was stored at room temperature for a period of 30 days. The quality of meal, drawn at 0th, 15thand 30th day was evaluated on the basis of total plate count, yeast and mould count and TBARS. TPC and yeast and mould count increased significantly (p<0.05) from 0th to 30th day. However feather meal prepared by biological method exhibited significantly (p<0.05) lower TPC and yeast and mould count than the other methods. TBARS increased significantly (p<0.05) with the storage time and varied between three treatments. Feather cum skin meal processed by biological degradation showed significantly (p<0.05) lower values of TBARS. It was observed that the increase in α-tocopherol level caused significant (p<0.05) decrease in TBARS values irrespective of the processing treatments. Results concluded that biological processing along with incorporation of α-tocopherol can be successfully used for the production of shelf stable feather cum skin meal.
Keywords : Feather cum Skin Meal Processing α-Tocopherol TBARS TPC
Introduction
Poultry industry has witnessed tremendous growth during the last few decades. Poultry slaughter yields many by-products viz. blood, offal’s (viscera, heads and feet) and feathers etc. These by-products can be utilized at industrial level. Feathers are being generated in large quantities as a by-product from commercial poultry processing industries. 8.5 billion tons of poultry feather are being produced as a by-product worldwide. India alone contributes 350 million tons of poultry feathers (Sarita and Neeraj, 2010). One of the challenges to the modern poultry industry is their disposal. Most feather waste is land filled, rendered, incinerated or buried which cause contamination of air, soil and water (Moreki and Charipasi, 2011). Feathers and skin of poultry can be utilized in the production of feather cum skin meal as an excellent animal protein feedstuff for livestock and poultry. Proper utilization of feathers as well as skin not only will prevent environmental pollution but also maximize returns for poultry producers. Feather meal can be prepared by various methods such as hydrothermal, chemical and biological. However, the biggest disadvantage with the hydrothermal treatment is that it leads to a destruction of essential amino acids like methionine, lysine, tyrosine, and tryptophan that in turn accounts to poor digestibility and low nutritional value (Tiwary and Gupta, 2012).The bioconversion of feathers into feather meal utilizing keratinolytic microorganisms produces a product with better digestibility and nutritional value (Werlang and Brandelli, 2005).
During storage of animal derived feed stuffs there occurs spoilage in terms of microbial proliferation and chemical degradation. This results in development of oxidative rancidity and production of toxic compounds which are injurious to health (Gotoh and Wada, 2006). Antioxidants are added to the feed to prevent the oxidation and enhance the shelf life of the feed. Vitamin E is a natural antioxidant and is significantly effective against the harmful effects of lipid oxidation (Gyula et al., 2005). There is scanty literature available regarding the storage study of feather meal. The current study was conducted with the objective of studying the effect of α-tocopherol on the shelf life of feather cum skin meal prepared by three different processing methods.
Materials and Methods
Feather cum skin meal was prepared by the method of Boushy and Vander (2000) with slight modification. The meal obtained by modified hydrothermal rendering was subjected to chemical and microbial treatment as per standardized method (Papdopoulos, 1985). In chemical degradation, meal was mixed in 0.2% NaOH and heated at 80±5oC for 10-15 min (Papadopoulous, 1985). Neutralization of meal was done with 35(%) HCL and distilled water. The meal was then subjected to oven drying followed by grinding in blender. In microbial degradation, the lyophilized Bacillus licheniformis culture procured from IMTECH was used for degradation after its revival. The method described by Xiang et al. (1992) was followed for the preparation of basal media. Swetlana and Jain’s (2010) method was followed for microbial degradation of feather with slight modifications. Feather cum skin meal prepared by all the three methods was treated with anti-oxidant α-tocopherolat two levels viz, 400 ppm (T1) and 800 ppm (T2). The meal without α-tocopherol was kept as control (C).TBARS value was done by following the method of Wright et al. (1981) with slight modifications. The amount of malonaldehyde (MDA) formed in each of the samples was assessed by measuring the optical density of the supernatant at wavelength of 532 nm using UV-VIS spectrophotometer (HITACHI, UV-Spectrophotometer U-1800, Japan).The estimation of The TBARS value was calculated as mg malonaldehyde per kg of sample by multiplying O.D. value with k factor 5.2. Microbiological analysis in terms of total plate count and yeast and mould count of samples was conducted as per Maturin and Peeler (2001) and Tournas et al. (2001) respectively. Statistical analysis was carried out using two way ANOVA and by using SPSS ver 20.
Results and Discussion
The proximate composition of feather cum skin meal prepared by three different methods is given in Table 1. Meal prepared by MT showed significantly higher protein content than in HT and CT. Fat content was significantly lower in meal prepared by MT than in HT and CT.
Table 1: Proximate composition of feather-cum-skin meal prepared by HT, CT and MT methods (Mean±S.E)
Treatment | HT | CT | MT |
Moisture (%) | 7.99 ± 1.20 | 8.43 ± 1.32 | 8.05 ± 1.40 |
Crude Protein (%) | 44.90 ± 1.68a | 74.96 ± 0.96b | 76.55 ± 1.73b |
Ether extract (%) | 12.28 ± 0.44b | 12.18 ± 0.72b | 8.82 ± 0.18a |
Ash (%) | 0.43 ± 0.26 | 0.47 ± 0.27 | 0.40 ± 0.05 |
Means across the rows with different superscript differ significantly (p<0.05)
Storage Study
Thiobarbituric Acid Reacting Substance (TBARS) Value
The results pertaining to the TBARS (mg MDA g-1) of feather-cum-skin meal prepared by three processing methods viz. HT, CT and MT are presented in Table 1. On 0th day TBARS values of C in all cases was significantly (P<0.05) higher than T1 and T2 within each method whileT2 showed significantly (P<0.05) lower values than T1. The TBARS values revealed similar trend on 15th and 30th day of storage. The lower TBARS values in T1 and T2 can be attributed to the incorporation of α-tocopherol as an antioxidant that has helped in decreasing the malonaldehyde formation during storage. The decreasing trend in the malonaldehyde values from T1 to T2 is probably because of increasing the level of α-tocopherol in the said treatments. Same observation was reported by Villwock and Hartfiel (1982) who found that by increasing the amount of antioxidants in the mixed feeds, fat oxidation was less intensive. The results were in agreement with those of El-Lakany and March (1974) who reported that 0.025 (%) ethoxyquin stabilized the meal lipids against oxidative changes and malonaldehyde formation. The results were also in agreement with Anjum et al. (2004), Para et al. (2017) and Waheed et al. (2004) who reported a decrease in fat oxidation with the addition of antioxidants.
As revealed in Table 2 within each method of preparation (HT, CT and MT) TBARS values in all treatments showed significant difference (p<0.05) between days and increased linearly (P<0.05) throughout the storage period.
Table 2: TBARS value of feather-cum-skin meal prepared by HT, CT and MT methods
TBARS (mg MDA g-1) | |||||||||
HT | CT | MT | |||||||
Day | C | T1 | T2 | C | T1 | T2 | C | T1 | T2 |
0th | 2.44± 0.10cA2 | 2.10 ± 0.11bA2 | 1.85 ±0.16aA2 | 2.39 ± 0.10cA2 | 2.01 ± 0.19bA2 | 1.83 ± 0.32aA2 | 2.13 ± 0.11cA1 | 1.84 ± 0.15bA1 | 1.64 ± 0.13aA1 |
15th | 2.82 ± 0.98cB2 | 2.38 ± 0.42bB2 | 2.13 ±0.00aB2 | 2.70± 0.75cB2 | 2.32 ± 0.64bB2 | 2.24 ± 0.48aB2 | 2.43 ± 0.29cB1 | 2.10 ± 0.16bB1 | 1.99 ± 0.40aB1 |
30th | 3.48 ± 0.39cC2 | 3.00 ± 0.16bC2 | 2.79 ±0.21aC2 | 3.37 ± 0.14cC2 | 2.93± 0.28bC2 | 2.72 ± 0.28aC2 | 2.89 ± 0.47cC1 | 2.61 ± 0.00bC1 | 2.33 ± 0.00aC1 |
*Mean± SE with different superscripts in a row wise (lower case alphabet) and column wise (upper case alphabet) differ significantly (P<0.05); Mean± SE with different superscripts in a row (numerals-1, 2) of same treatment (T0, T1 and T2) within HT, CT and MT differ significantly (P<0.05)
The lower values of T2 on each day were due to addition of antioxidant (α-tocopherol) causing decreased fat degradation in the meal prepared by HT, CT and MT. The results in the present study were in line with the observations of Franic (1985) who studied the effect of storage on fish meal for 4-10 months at different temperatures (18-40°C) and reported that the TBARS value increased from 10-15 during prolonged storage in feeds with and without antioxidants. The results of the current study were in agreement with the results of Ozogul et al. (2006) who found a linear correlation with the TBARS value, fat content and the storage duration of the commodity. They concluded that higher TBARS value may be due to higher fat content (2.375 to 28.85 %) in hatchery waste samples. Comparative evaluation of three methods (HT, CT and MT) revealed that on each day the TBARS values of all treatments viz; C, T1 and T2 was found non-significant (p>0.05) between HT and CT. However, the TBARS values of all three treatments within MT were significantly (p<0.05) lower than obtained in case of HT and CT. This could be due to lower fat content obtained in the meal prepared by MT. They concluded that higher TBARS value may be due to higher fat content (2.38 to 28.85 %) in hatchery waste samples.
Microbiological Quality
Total Plate Count
The results pertaining to the total plate count (log10 cfu/g) of feather cum skin meal prepared by three processing methods viz. HT, CT and MT are delineated in Table 3.The TPC values in all cases showed significant (p<0.05) increase from 0th to 30th day. Within each method (HT, CT and MT) the average TPC (log10 cfu/g) of C was significantly higher than T1 and T2. This significant (p<0.05) difference was observed on 0th, 15th and 30thday of storage. On comparing the different methods of preparation of feather cum skin meal it was observed that the TPC values for each treatment in case of HT were significantly (p<0.05) higher than the respective treatments within CT and MT albeit a non-significant (p>0.05) difference between the later two. This could be due to incorporation of α-tocopherol and different processing methods employed for preparation of the meal. The results corroborated with Okonko et al. (2010) who reported that the microbial loads of poultry feeds sold in Nigeria ranged from 0.65 x 107 to 1.23 x 109cfu/g. The results were also in agreement with the results of Jeyasanta and Patterson (2014) who reported the TPC value of Grade I, Grade II, Grade III and Grade IV fish meal as 2.3 x 102, 3.9 x 103, 2.0 x 108 and 2.4 x 103 cfu/g, respectively.
Table 3: Total plate count of feather-cum-skin meal prepared by HT, CT and MT methods
Total Plate Count (log10 cfu/g) | |||||||||
HT | CT | MT | |||||||
Day | C | T1 | T2 | C | T1 | T2 | C | T1 | T2 |
0th | 2.34 ± 0.27cA2 | 2.09 ±0.79bA2 | 1.99±0.89aA2 | 2.22±0.54cA1 | 1.87±0.69bA1 | 1.79±0.12aA1 | 2.20±0.23cA1 | 1.80±0.25bA1 | 1.70±0.87aA1 |
15th | 2.79 ± 0.15cB2 | 2.58 ± 0.75bB2 | 2.29 ± 0.61aB2 | 2.56 ± 0.75cB1 | 2.39 ± 0.55bB1 | 2.19 ± 0.57aB1 | 2.50 ± 0.29cB1 | 2.30 ± 0.16bB1 | 2.00 ± 0.55aB1 |
30th | 3.51± 0.81cC2 | 3.09± 0.71bC2 | 2.75 ± 0.00aC2 | 3.10 ± 0.12cC1 | 2.80 ± 0.14bC1 | 2.35 ± 0.13aC1 | 2.99 ± 0.11cC1 | 2.79 ± 0.12bC1 | 2.31 ± 0.11aC1 |
*Mean± SE with different superscripts in a row wise (lower case alphabet) and column wise (upper case alphabet) differ significantly (P<0.05);Mean± SE with different superscripts in a row (numerals-1,2) of same treatment (T0, T1 and T2) within HT, CT and MT differ significantly (P<0.05)
Yeast and Mould Count
As delineated in Table 4 yeast and mould count (log10 cfu/g) of C, T1 and T2 increased significantly (p<0.05) from 0th to 30th day irrespective to the method of preparation. Within each method C showed significantly (p<0.05) higher yeast and mould count than T1 and T2 during 30 days storage. Among the different methods HT revealed significantly (p<0.05) higher yeast and mould count in all the treatments than CT and MT whereas non-significant (p>0.05) difference was observed between the later two. It was observed that yeast and mould count for all treatments was highest in HT and exceeded the satisfactory limit on 30th day. The results were in agreement with Chelkowski (1991) who reported that the amount of microscopic fungi in the fish meal should not be higher than 1×105 cfu/g. The results of the current study were more or less in agreement with that of Labudaet al. (2005) and Kubiznaet al. (2011) wherein they both reported the fungal count in the poultry feed ranged from 102 -104cfu/g.
Table 4: Yeast and mould count of feather-cum-skin meal prepared by HT, CT and MT methods
Yeast and Mould(log10 cfu/g) | |||||||||
HT | CT | MT | |||||||
Day | C | T1 | T2 | C | T1 | T2 | C | T1 | T2 |
0th | 3.00 ±0.80cA2 | 2.62 ± 0.10bA2 | 2.39 ± 0.87aA2 | 2.79±0.84cA1 | 2.41±0.04bA1 | 2.29 ± 0.10aA1 | 2.61 ± 0.70cA1 | 2.39 ± 0.20bA1 | 2.25±0.53aA1 |
15th | 3.52 ± 0.33cB2 | 3.36 ± 0.04bB2 | 3.07 ± 0.24aB2 | 3.27±0.04cB1 | 2.99±0.32bB1 | 2.80 ± 0.13aB1 | 3.20 ± 0.39cB1 | 2.59 ± 0.75bB1 | 2.73±0.12aB1 |
30th | 3.89 ± 0.02cC2 | 3.49 ± 0.02bC2 | 3.29 ± 0.04aC2 | 3.49±0.02cC1 | 3.11±0.01bC1 | 2.93 ± 0.16aC1 | 3.40 ± 0.03cC1 | 3.05 ± 0.11bC1 | 2.89±0.06aC1 |
*Mean± SE with different superscripts in a row wise (lower case alphabet) and column wise (upper case alphabet) differ significantly (P<0.05);Mean± SE with different superscripts in a row (numerals-1,2) of same treatment (T0, T1 and T2) within HT, CT and MT differ significantly (P<0.05)
Conclusions
The incorporation of α-tocopherol at 800 ppm in the meal resulted in decreased lipid oxidation and during 30 days storage TBARS values were within the acceptable limit. TPC and yeast and mould count of feather cum skin meal increased linearly during entire storage period of 30 days. However, the meal containing 800 ppm of α-tocopherol showed lower values during 30days storage. Among the different methods, MT yielded product of improved quality and remained shelf stable for 30 days.
References