Effect of Barley Flour on Quality of Restructured Spent Hen Meat Blocks

Poultry industry is one of the fastest growing industries in the world and has been recognized as a vital sector that ensures food security through egg and meat. Replacement of old spent hens stocks before winter lead to abundant spent hen meat available for processing of value added products. The meat of these birds is often associated with undesirable characteristics due to chewy and tough nature and fetches lower price in the market (Abe et al., 1996). The efficient and economical technology for processing such undervalued meat may result in its better utilization.
       
In recent years, the consumer’s perception about the nutrition and meat preference has been changed considerably because of many factors including changes in lifestyle, smaller family size, the requirement for more lean and less fat and the desire for more convenience etc. Changing consumer demands and increasing global competition are causing meat product manufacturing sector to embrace new processing technologies and new ingredient systems. Restructuring is a processing technique used for developing convenience products with texture in between intact steak and comminuted product. The restructuring process makes it possible to create various new products for different markets. Meat and meat products can be tailored into more “healthier” form by adding ingredients considered beneficial for health. Barley (Hordeum vulgare) is also recognized as a functional grain because it contains high levels of β-glucan and phytochemicals. It is an excellent source of bioactive constituents such as vitamin E (including tocotrienols), B-complex vitamins, minerals, phenolic compounds, soluble and insoluble dietary fiber (Madhujith et al., 2006). Barley has one of the highest levels (up to 6%) of β-glucan, classified as soluble dietary fiber. β-glucan is a water soluble hydrocolloid that functions to provide water control by thickening and gelling. Today β-glucan has achieved functional status due to its beneficial physiological effects. β-glucan has been implicated in lowering plasma cholesterol, improving lipid metabolism, reducing glycaemic index and prevention of hepatic damage by reducing taxol-induced hepatic damage (Behall et al., 2006; Keenan et al., 2007; Karaduman et al., 2010). The Food and Drug Administration have allowed whole grain barley and barley-containing products to carry a claim that they reduce the risk of coronary heart disease. Various products processed from barley are available in the market and gaining popularity as functional foods (Sharma and Kotari, 2017). Considering the associated functionality of barley, the present study was undertaken to evaluate the quality of restructured spent hen meat blocks formulated with barley flour.

Sources of raw material
 
Live spent hens (White Leghorn) were procured from Central Avian Research Institute, Izatnagar, dressed and deboned manually in the experimental abattoir of Division of Livestock Products Technology, IVRI, Izatnagar. Analytical and food grade chemicals were procured from Qualigens, Mercks, BDH and S.D. fine. Refined salt (Tata Chemicals Ltd., Mumbai), refined wheat flour (maida), barley flour, onion and garlic were procured from local market of Bareilly (U.P.). Condiments were prepared by mixing onion and garlic in 3:1 ratio. Spices were prepared in laboratory as per pre-standardized formulation.
 
Product preparation
 
Restructured spent hen meat blocks (RSHMB) were prepared by the pre-standardized formulation (Gupta et al., 2015). Spent hen meat was cut manually into 1-1.5 cm² small chunks and massaged in paddle mixer along with salt, sodium tripolyphosphate, sodium nitrite, ice, spice mix, condiments, maida and barley flour. Barley flour (1:1 hydration, w/w) was incorporated at the levels of 4, 6 and 8% by replacing lean meat in the formulation. The mix was stuffed into aluminium moulds, cooked for 50 min under steam without pressure and cut into uniform slices of 7 mm width with food slicer. The formulation of RSHMB with different levels of barley flour is given in Table 1.
 

 
Product yield
 
The product yield was calculated by the following formula:
  pH
 
The pH of restructured spent hen meat blocks was determined by the method described by Troutt et al., (1992).
 
Proximate composition
 
Moisture, protein, crude fat and ash contents of restructured spent hen meat blocks were determined by standard procedures of Association of Official Analytical Chemist (AOAC, 2007).
 
Moisture: Protein ratio
 
Moisture: Protein ratio of RSHMB was determined from the derived values.
 
Shear force value
 
Shear force value was determined by method of Berry and Stiffler (1981) using Warner-Bratzler Shear Press (81031307 GR Elec. MFG. Co. USA).
 
Texture profile analysis
 
The texture profile analysis of RSHMB was performed using texture analyzer following the procedure by Bourne (1978). The samples were made by cutting RSHMB into 1 cm3 and compressed by a compression probe (P75) at a crosshead speed of 10 mm/sec through a two cycle sequence, using a 50 kg load cell. Texture profile parameters viz. hardness, adhesiveness, springiness, cohesiveness, gumminess and chewiness were analyzed.
 
Sensory evaluation
 
The restructured spent hen meat blocks were cut into uniform slices with food slicer (Electrolux H 300) and subjected to sensory evaluation by experienced panel of the scientists and postgraduate student of Division of Livestock Products Technology, Indian Veterinary Research Institute, Izatnagar. The samples were presented to the panelists after assigning suitable codes and evaluated for sensory attributes viz. general appearance, flavour, juiciness, texture, binding and overall acceptability using 8-point descriptive scale (Keeton, 1983), where 8 = excellent and 1 = extremely poor. The nature of experiment was explained to the panel without disclosing the identity of the samples. Plain water was provided to rinse the mouth between the samples.
 
Statistical analysis
 
The experiment was replicated three times. The data obtained from the experiments were analyzed statistically for analysis of variance (ANOVA), Duncan’s multiple range test and least significance difference test using SPSS 16.0 software package developed as per the procedure of Snedecor and Cochran (1995).

Mean values of the physico-chemical properties of restructured spent hen meat blocks (RSHMB) incorporated with different levels of barley flour (1:1 hydration, w/w) are presented in Table 2. There was a gradual increase in the product yield of RSHMB with increase in the level of barley flour and it was significantly higher (P<0.05) at 6 and 8% level as compared to control. Increase in the product yield with barley flour could be attributed to the gelatinizing property of starch component on heating (Comer, 1979). Bond et al., (2001a) also reported increase in product yield of low fat ground beef patties with addition of barley. The pH of RSHMB prepared with different levels of barley flour was significantly higher (P<0.05) than that of control, however it was comparable among the treatments. The increase in pH of RSHMB could be attributed to neutral nature of barley flour and decreasing level of lean meat in treated samples. Morin et al., (2002) also reported an increase in the pH of breakfast sausages formulated with barley β-glucan. The moisture percentage of RSHMB was significantly lower (P<0.05) at 6 and 8% levels of barley flour, however, it was comparable at 4% level with that of the control. Decrease in moisture percentage might be attributed to the comparative increase in the dry matter content due to replacement of meat with barley flour. The findings are in accordance with Kumar and Sharma (2006) who also reported similar result in chicken patties prepared with hydrated (1:1, w/w) barley flour. Protein percentage of control product was significantly higher (P<0.05) than RSHMB prepared with 6 and 8% barley flour incorporation. The fat percentage of RSHMB recorded a gradual decrease with increase in level of barley flour and was significantly lower (P<0.05) at 8% level of barley flour as compared to control. Gradual decrease in the protein and fat percentage might be attributed to the replacement of lean meat with barley flour, which is low in protein and fat as compared to spent hen meat. There was a gradual decrease in ash percentage with increase in the level of barley flour and it was significantly lower (P<0.05) at 6 and 8% levels as compared to the control. It might be due to lower mineral content of barley flour as compared to lean meat. Similar findings for protein, fat and ash percentage were also reported by Ahmed et al., (2015) in restructured buffalo meat fillets.
 

       
Moisture to protein ratio of restructured spent hen meat blocks showed an increasing trend with increase in the level of barley flour and it was significantly higher (P<0.05) at 6 and 8% levels of barley flour as compared to control. Moisture binders enhance the ability of protein fibers to bond with water which tenderizes the meat and also improve the product yield. There was a gradual decrease in the shear force values of RSHMB with increase in level of barley flour and it was significantly lower (P<0.01) at 8% level than that of control. Progressive decrease in shear force values of RSHMB with increasing level of barley flour could be due to reduction in compactness that allowed the shear blade to pass with ease. This is in agreement with other workers who also reported an increase in moisture to protein ratio and decrease in shear force value as a result of barley flour incorporation in different meat products (Khate, 2007; Kumar, 2013).
       
Mean sensory scores of restructured spent hen meat blocks incorporated with different levels of barley flour (1:1 hydration, w/w) are presented in Table 3. There was no significant difference (P>0.05) in the general appearance of control and RSHMB incorporated with different levels of barley flour. Flavour score of RSHMB declined gradually with increase in the barley flour incorporation, although the product still scored very good flavour rating. Gelatinization of starch produces numerous pores on the surface of starch granules especially at high temperatures (Buttery et al., 1999). These numerous pores probably play an important role in interacting with flavor components. Similar findings were reported by Kumar and Sharma (2006) in chicken patties incorporated with barley flour. There were no significant differences (P>0.05) in the scores for texture, binding, juiciness and overall acceptability of RSHMB of control as well as those incorporated with different levels of barley flour. Scores for all the sensory attributes had a very good rating at different levels of barley flour. Titov et al., (1994) reported that poultry sausages incorporated with barley had comparable sensory properties with control. Bond et al., (2001b) observed better acceptability in beef patties with the incorporation of 10% hydrated barley into beef mince.
 

       
Texture profile analysis of RSHMB (Table 4) revealed that there was a gradual decrease in hardness of RSHMB with increase in level of barley flour. It was significantly lower (P<0.05) at 6 and 8% level of barley flour. It might be due to the increase in concentration of hydrocolloid. Alveraz and Barbut (2013) also reported reduction in the hardness of cooked meat emulsion with increase in β-glucan. There was no significant difference (P>0.05) in the springiness of products with different levels of barley flour. Cohesiveness, gumminess and chewiness of RSHMB with 8% barley flour were significantly lower (P<0.05) than that of control. Decrease in hardness, cohesiveness, gumminess and chewiness have also been reported with incorporation of 10% hydrated cracked waxy hull-less barley in beef patties (Bond et al., 2001 b). Some people with mastication and/or swallowing problems require texture-modified nutritious soft meat products because they face difficulty to bite and chew stiff meat eg. babies and old people. The developed restructured spent hen meat blocks with 8% barley flour can be utilized for this purpose.
 

       
The production cost of restructured spent hen meat blocks incorporated with 8% barley flour was determined and compared with control. The cost of raw materials, depreciation cost of machineries, cost of electricity, packaging, labour, water, rent and maintenance have been mentioned in Table 5. The depreciation of the equipment was considered at the rate of 10%. Electric charges include the consumption of electricity in the preparation of RSHMB in term of power utilized by the Paddle mixer 3.0 KWH unit, Food slicer  0.6 KWH, Geyser 8.0 KWH, Steam cooker 1.2 KWH, Refrigerator 6 KWH, Deep freezer 3 KWH, Air conditioner 36 KWH and light etc. 5.0 KWH, respectively. The cost of 1.0 kg of printed LDPE pouches was Rs. 120/kg. Maintenance cost used to maintain equipments, building and premises were also considered. It was noted that restructured spent hen meat blocks developed by incorporating barley flour resulted in reduction of production cost by Rs. 18.4/kg than that of control.

On the basis of physico-chemical, sensory and textural properties, the optimum incorporation level of barley flour for preparation of restructured spent hen meat blocks was adjudged as 8%. Incorporation of barley flour improved palatability as well as product yield of restructured spent hen meat blocks.

The authors sincerely thank to the Director, Indian Veterinary Research Institute, Izatnagar for providing the required facilities to carry out the research work. The first author is highly obliged to Indian Council of Agricultural Research, New Delhi for providing financial assistance in the form of Senior Research Fellowship during PhD.