​Effect of Bael (Aegle marmelos L.) Pulp Residue on Quality and Storability of Chicken Meatballs from Spent Layers

Changes in existing food habits and lifestyle patterns have led the people to search for affordable and healthier foods with satisfactory taste and pleasant appearance. Consumers’ expectations are healthy foods with all natural ingredients and do not contain any artificial flavour, colouring ingredient or chemical preservative, or any other artificial or synthetic ingredient.
 
Despite meat having a high biological value, having high protein, excellent source of some essential fats, soluble vitamins and minerals (Yadav et al., 2020; Gálvez et al., 2019) , it has a number of ailments on the human body such as colon cancer, cardiovascular diseases and obesity on regular consumption (Boada et al., 2016). It lacks dietary fibre in which documentary evidence supports that intake of fibre diminishes the threat of such diseases (Lockyer et al., 2016). Therefore, the meat industry continuously seeks to adapt and develop new formulations designed to increase shelf life, quality and safety of foods. Their efforts are using natural ingredients such as antioxidants, vitamins, minerals or fibre from plants and plant materials which are rich in bioactive compounds (e.g. phenolics and flavonoids compounds) to improve the quality of meat.
 
The bael fruit contains bioactive compounds such as polyphenols, flavonoids, carotenes, vitamins, organic acids (Hazra et al., 2020) and essential minerals (i.e. potassium, calcium, phosphorous, sodium, iron,  copper and manganese (Manandhar et al., 2018) that show multiple biological activities like, antibacterial, antihelminthic, anticancer, antiulcer, antidiarrhea,  astringent, antidiabetic, anti-inflammatory and antioxidant properties, etc. (Lim, 2012; Sarkar et al., 2020). It also contains a good source of dietary fibre (Sawale et al., 2018).
 
This experiment was conducted to see the effect of bael pulp residue powder on quality and storability of chicken meatballs from spent layers stored at refrigerated temperature (4±1°C) so that quality of meat can be improved and shelf life can be increased.

The study was carried out during the month of April, 2021 to September, 2021 as per the designed program in the Department of Livestock Products Technology, Faculty of Veterinary and Animal Sciences of West Bengal University of Animal and Fishery Sciences, Belgachia, Kolkata.
 
Raw materials
 
Spent layer birds, aged more than 80 weeks, were procured from the market and were subjected to ante-mortem inspection and maintained for 6 hours by giving water only. Those birds were slaughtered and dressed as per the standard procedure mentioned by Sahoo and Panda (1983) with little bit modification.
 
Bael pulp residue was placed into the sun for drying. After complete drying, powder was made by grinding it through a grinder. Then, this powder was sieved through a fine mesh for obtaining particle size of <1.0 mm (Costa et al., 2009).
 
Peeled onion, garlic and ginger were blended in the ratio of 3:1:1, respectively, to make a fine paste. Other spice mixtures were turmeric (haldi) (10%), black pepper (8%), coriander (15%), aniseed (10%), red chilli (10%), caraway seed (10%), cinnamon (5%), cardamom (5%), clove (5%), cumin seed (10%), nutmeg (1%), mace (1%), dried ginger (10%). Those spices were powdered, weighed and mixed thoroughly.
 
Meatball emulsions
 
Meat was cut into small chunks and placed in the meat mincer by using a 10 mm plate followed by a 5 mm diameter plate subsequently. Then, emulsions were prepared by adding lean meat (70%), salt (1.6%), tripolyphosphate (0.3%), sugar (0.3%), ice flakes (8.7%), sodium nitrite (0.015%), rice bran oil (7.0%), dry spice mix (1.80%), refined wheat flour (5%), egg albumin (1.285%) and condiment mixture (4%).
 
Meatballs preparation
 
Meatball emulsion was equally divided into 4 parts; one was made for control and three were made for treatments. Treatments were incorporated with bael pulp residue powder at three different levels viz. 1.0%, 1.5% and 2.0%, respectively, on w/w basis. Now, uniformed meatballs (diameter 2 cm) were made from each part mechanically. Meatballs were put in metal containers and steam cooked at 121°C temperature for 20 minutes under a pressure of 6.8 kg (Kumar et al., 2013). Cooked meatballs were cooled at room temperature. One portion from each part was taken for testing on 0 day and the rest were kept under refrigerated condition (4±1°C) for succeeding analysis.
 
Parameters tested
 
Proximate analyses were determined as per the methods described by (AOAC, 2001). Texture profile analysis of cooked meatballs was determined by TA-HDi Texture Analyzer (Stable Micro Systems, UK). The peroxide value was estimated as per procedure mentioned by Koniecko (1979) with slight modifications. TBA value was determined by the same procedure mentioned by Tarladgis et al., (1960). DPPH scavenging activity was measured as per procedure mentioned by Kato et al., (1988). Microbiological parameters were determined by the same procedure mentioned in APHA, 2001. Sensory parameters were evaluated by 10-members sensory panelists of trained judges of different age groups and sexes by using 9-point Hedonic scale as described by Wichchukit and O'Mahony (2015).
 
Statistical analysis
 
IBM® SPSS® software was used for analyzing the data. Univariate data were analyzed by the statistical method of ANOVA according to Tukey’s HSD (Honest Significant Dif ference) Test (Tukey, 1949).

 
Proximate analysis (Table 1) showed that moisture percentage, crude protein and crude fat decreased (p<0.05) gradually with the increased concentration of BPR powder percentage. But, crude fibre increased (p<0.05) gradually with the increased concentration of BPR powder percentage.  These results are congruent with the results reported by Das et al., (2014). Moisture, crude protein, Crude fibre and crude fat (%) of cooked meatballs gradually (p<0.05) decreased for all samples with the increase of storage period from 0 to 15 days at 4±1°C. Similar findings were reported by Giri et al., (2019).
 

 
 
Texture profile analysis
 
The control samples had the higher hardness, cohesiveness, gumminess and chewiness values, whereas the samples treated with 1% BPR showed the highest springiness (Table 2). Reduction of hardness, springiness and cohesiveness were found with the increase of BPR in the meatballs. Hardness relies on the moisture percentage of meatballs. Springiness is the ability of the product to recapture its shape after deformation during the pressure cycle. Springiness values were related with the elastic properties of meatballs. Thus, decrease of springiness demonstrates that the elasticity of meatballs is diminished with the increase level of incorporation of BPR powder. Increases of gumminess and chewiness were seen with the increase of BPR in the meatballs. Gumminess and chewiness values are related by hardness, cohesiveness and springiness values of the product. Incorporation of BPR in the meatballs leads to increase in chewiness significantly (P<0.05). These results are in agreement with the results reported by Das et al., (2020) and Rindhe et al., (2018). There was a gradual decrease in hardness, springiness, cohesiveness, gumminess and chewiness of all samples with an increase of the storage period from 0 to 15 days.
 

 
Oxidation and antioxidant properties
 
As described by Kumar et al., (2015), during process of lipid oxidation, unsaturated fatty acids are oxidized and hydroperoxides are formed that decompose rapidly, resulting in a large number of secondary compounds including hydrocarbons, aldehydes, ketones, alcohols, esters and acids. These compounds are responsible for unpleasant smells in meat products. Bael fruit has good antioxidant properties (Hazra et al., 2020). This is the reason for having low TBA value but having high value of DPPH radical scavenging activity with the increase concentration of BPR powder in the meatballs and the same trend has been seen during increase of storage period (Table 3). TBA value increased gradually and DPPH radical scavenging activity decreased gradually with the increase of storage period from 0 to 15 days.
 

 
Microbiology
 
Result of total plate count and yeast and mould count  (Table 4) showed that incorporation of BPR on cooked meatballs was very much effective (P<0.05) in controlling the microbial counts throughout the storage period of 15 days at 4±1°C. Microbial counts in meat products decreased with the increase of BPR in meatballs. BPR is having antimicrobial properties due to contain of polyphenolic compounds. Similar results were found by Ruhil et al., (2011) where he reported that bael is effective against bacteria and fungus. Das et al., (2014) and Vidyarthi et al., (2021) also reported that BPR is effective against total plate count.
 

 
Sensory analysis
 
Table 5 shows the organoleptic attributes. Appearance was significantly (P<0.05) higher than control. Increase of flavour was observed with the increase of BPR in the meatballs. This could be due to the reason that BPR might have acted as stabilizing agent for retaining the flavour by inhibiting the lipid oxidation. Overall acceptability scores in treated products remained stable. All attributes were acceptable even on the 15^th day of storage. Similar findings reported by Anandh (2014).
 

BPR powder has had positive effects in meatballs on almost all the parameters. Among the treatments, 2% BPR powder incorporated in chicken meatballs form spent layers showed the best results by analysing above mentioned data of physico-chemical parameters, antimicrobial properties and sensory attributes. Commercial industries are making meat products or other similar products that contain chemical preservatives, synthetic antioxidants, antimicrobial contents and other chemicals which are unhealthy and result in some degenerative diseases and saturated fats. But, by using natural products, industries can avoid input of all types of chemicals in their products. Therefore, the incorporation of BPR powder can be used in meat and meat products or similar muscle food products for preserving meat quality, extending shelf-life, preventing economic loss and fulfilling customer satisfaction.

This is a part of Ph.D. thesis work. The author is thankful to the Department of Livestock Products Technology, West Bengal University of Animal and Fishery Sciences and acknowledges the financial assistance for carrying out the research work.

None.