Physical quality and consumer acceptance of beef patties containing different levels of moringa oleifera leaf flour extract

The aim of this study was to determine the effect of Moringa oleifera leaf flour extract (MOLFE) utilization on medium beef patties. The addition levels of MOLFE were set at 0 (P0), 2 (P1) and 4% (P2) (w/w). A total of 25 semi-trained panellists was asked to evaluate consumer acceptance using a preference measurement instrument of a 9-point hedonic scale. The physical quality and hedonic test data were analysed using analysis of variance followed by the Tukey test for a significantly different data. This study revealed a notable effect of MOLFE on raw patties pH (p<0.05), wherein its addition markedly decreased the raw pH value. No significant effect was observed for cooked pH, cooking loss and water holding capacity (WHC). Likewise, the hedonic test result was not differed among treatments (p>0.05), indicating acceptable inclusion of MOLFE into beef patties up to 4%. This study suggests the utilization of MOLFE up to 4% level can be applied to the manufacture of beef patties while maintaining its consumer acceptance.


Introduction
During the manufacturing of meat products, synthetic antimicrobial and antioxidant are commonly added to extend its storage periods.Due to a possibility of residue formation from continues consumption of chemically added products which can endanger consumers' health, it is necessary to look for alternatives to these chemicals.Several bioactive substances have been screened from plant materials that can replace the function of these chemicals, including polyphenols [1].The polyphenols interfere the homeostatic state of microbial via blocking of nutrient uptake and transport, and biosynthetic interference of amino and nucleic acid, leading to cell lysis and death [2,3].Therefore, studies involving polyphenols to donate functional attributes toward meat products have been object of interest [2,4,5].Of which, moringa (Moringa oleifera) as a food additive that is useful as a functional food has been applied.The presence of bioactive compounds as natural antioxidant in moringa can prevent lipid oxidation and unwanted chemical reactions that cause damage to meat products.In addition, it can also improve the nutritional content, safety and physicochemical characteristics of the meat product [6].
The addition of ingredients from vegetable sources to meat products such as patties, burgers and nuggets is gaining popularities among consumers due to its minimum detrimental effect on health.The selection of these ingredients is mainly focus on screening functional food content such as protein and other nutrients with health benefit effects [7].Numerous studies utilizing moringa leaves as a food additive have been performed on beef burgers.[8] suggested the addition of 6% moringa seed flour to still maintain consumer acceptance.Besides, using moringa leaf meal up to 0.8% from total meat used [9] or processing cooked goat meat patties containing leaf flour up to 0.9% of the total meat used [11] have been performed and revealed its positive effect.Furthermore, other researchers reported the utilization of moringa leaf extract flour up to a level of 5% for mutton patties [10] and 20% in chicken burgers [12].Conducted studies draw similar conclusion from the inclusion of the moringa plant in meat products to increase its nutrient content, maintain and improve physical quality, decrease lipid oxidation and extend its shelf life [13].Nevertheless, the addition of the moringa plant to meat products has the drawback of reducing the consumers preferences [9].This decrease in quality is caused by saponins and phenols that exist within the moringa, including isoflavones, catechins, and phenolic acids [14].
Considering its potential effect to increase quality attributes of meat products, however, it is necessary to understand the optimum inclusion level to avoid the decrease in both physical quality and consumer acceptances.Based on this background, this research was conducted to evaluate the effect of the use of moringa plant extract powder on the physical quality and level of consumer acceptance of beef patties.

Materials and methods
Beef patties were produced from rump meat with the addition of tapioca flour, eggs, ice and spices (salt, sugar, stabilizer).The treatment level used was moringa plant extract flour with a concentration of 2 and 4%.The beef patties formulations are shown in Table 1.Rump of beef and eggs were purchased from supermarkets, while tapioca flour and seasonings were from commercial brands.MOLFE flour used commercial flour that is standardized (food grade).All ingredients used in the manufacture of beef patties have food grade standard.The formulation and method of making beef patties were based on research by [15].The modification of patties formulation was in the use of ingredients and the percentage of the amount.For the manufacturing method, the modification was using a meat grinder with a diameter of 1 mm and a mixer used using an electric machine.

Table 1. Beef patties formulation with varying levels of moringa meal extract
No.
Ingredients ---------------------------------------%-------------------------------------- The beef patties physical test parameters include raw pH, cooked pH, cooking loss and WHC.The pH value was assessed using a pH meter according to [16] by grinding 10 g of sample and mixing it with 10 ml of distilled water until homogeneous and then measuring.The cooking loss was determined by weighing 50 g of the sample and boiling it in a water bath at an internal temperature of approximately 71°C for 6 minutes.The difference in weight between before and after boiling is used to calculate the percentage of cooking loss [17].The water holding capacity was evaluated using the [18], by weighing 0.3 g of sausage and pressing it with a weight of 35 kg for five minutes.The WHC value was calculated by subtracting the total water content from the free water content.The hedonic test analysis process used a 9-point hedonic scale according to the [19] method.The selection of panelists was done by selecting 35 students with the best grades from 75 people based on questionnaires provided.Panelists were given an explanation of the procedure for the hedonic test and filled out a consent form.The patties were warmed for about 15 minutes with a bain marie device and placed in a closed container which had been coded with 3 random numbers (3-digit number).A hedonic test was carried out by the panelists for each sample in each treatment.Panelists who have finished the hedonic test for each sample were asked to drink water and eat plain crackers to neutralize the taste and were then given 1 minute of rest.The hedonic test carried out in this study used standard testing rules for panelists as research subjects.
This study used an experimental design and one-way ANOVA statistical analysis.If there were significant differences in the mean treatment values, the analysis was continued using Tukey's test [20].Physical test used four replication sample for each treatment and hedonic test using 35 panelists as replication for each treatment.The analysis uses Minitab 17 software.

Results and discussion
Data from the analysis of the physical quality of beef patties with the supplementation of MOLFE levels are shown in Table 2.The results show that the raw pH was significantly different among MOLFE treatments in beef patties.However, limited effect on cooked pH, cooking loss and water holding capacity following MOLFE treatments were observed by this study.The addition of MOLFE markedly lower the value of raw pH in C1 and C2 beef patties.This decrease in pH could be due to the nature of the moringa flour added to the beef patties.Moringa leaf flour is acidic because most of the constituent proteins are acidic proteins or rich in acidic amino acids, such as aspartic and glutamic acids [21].
Several studies have shown different results from this study.The cooking losses and WHC values increased compared to the control with the addition of up to 0.9% moringa flour, but the pH level increased by 0.9% in cooked mutton patties [22].The utilization of moringa leaf extract on mutton patties stored for 0 days resulted in a pH value that was not differ from the control at levels up to 2%, but decreased at 3 and 5%.Furthermore, it was also stated that the cooking losses at the 1% level were the same as the control and had increased with the use of moringa leaf extract flour at a level of 5% [9].[13] stated that the pH of tilapia fish burgers with the addition of 0.2% moringa extract on day one was no different.Tilapia fish burgers with the addition of moringa flour had a pH of 6.5.The addition of moringa flower extract powder at 1 and 2% concentration into chicken nuggets was proven to reduce the pH value, while increase the cooking rate compared to that of controls [23].[24] elaborated that the addition of fresh moringa leaves to catfish nuggets up to a level of 15% had no effect on cooking loss, while the addition up to level of 5% did not detrimentally affect its WHC.The addition of 10 and 15% were reported to reduce the WHC value of catfish nugget.The addition of moringa flour up to 3% can increase the pH value and cooking loss in chicken meatballs [25].Some of these differences can be seen by the differences in the type of meat, type of product, type of moringa and level of moringa administration.Differences in the ingredients used, especially the type of meat and cooking method, can affect the quality of the patties, especially with the release of water and fat from the patties [26].Utilization of additional ingredients containing fiber and protein derived from plants can affect the quality of meat products such as burgers, patties, sausages, and nuggets.The use of plant materials is mainly related to the formation of gels and emulsions in these products.The type of plant, given concentration, and nutrient content of certain ingredients have different properties and functions upon their utilization, thus they may influence the physicochemical qualities and preferences of the product in different manner [14].
The pH value of cooked beef burgers with the addition of date fruit ranges from 5.90-5.94[27].The pH value of cured chicken meat products with the addition of moringa seed flour up to a level of 5% had a range of 5.73-6.19[28].In this study, the pH value was ranged from 5.07-5.62,meaning it has a lower value than other studies.Differences in pH can be caused by the ingredients being mixed and the method of cooking meat products [29].
The hedonic test data for beef patties with the addition of moringa extract flour up to a level of 4% is shown in Table 3.The results show that there was no significant difference between the treatment and the control with the addition of up to 4% level of MOLFE.This shows that the addition of diverse MOLFE levels gave the panelists the same hedonic value as the control.According to [30] in products with the addition of vegetable food ingredients such as moringa leaf flour, it has a weakness with the sensory characteristics of the moringa plant, resulting in low consumer acceptance of fortified meat products.In this study, sensory loss did not occur, possibly because the nutrient content that can affect the quality is covered by the nutrient content of other ingredients in the meat product formulation.According to [31], improving the quality of consumer acceptance can be done by optimizing the ingredients used in the burger formula, especially ingredients that produce certain compounds that play a role in the quality of the burger during cooking.
The results of this study compared to other researchers show differences and similarities.The value of colour, taste and overall acceptance of mutton patties with the addition of moringa flour up to 0.3% had non-significant values, but the juiciness and tenderness increased.Likewise, the use of 0.6 and 0.9% lead to a decrease in color, taste and overall, but an increase in juiciness and tenderness [22 According to [23], the addition of 1 and 2% moringa flower extract flour to chicken nuggets had no effect on sensory tests (appearance, flavor, texture, juiciness, overall acceptability).The supplementation of fresh moringa leaves at a level of 10 to 20% had no significant impact on color, taste and overall acceptability, but had a significant effect on the aroma and texture of the milkfish meatball samples.Furthermore, it was also stated that the addition of boiled moringa leaves at a level of 10 and 20% increased acceptance of aroma and taste, but color, texture and overall acceptance were not significantly different for milkfish meatballs [32].The addition of moringa flour at a concentration of 2% had no significantly different values in the hedonic test (appearance, flavor, texture, juiciness, overall acceptability) of chicken meatballs [25].The addition of fresh moringa leaves to catfish nuggets up to 15% had no effect on sensory tests of taste, aroma and texture, but reduced the color value of catfish nuggets [24].Some of these studies show similarities and differences in results with this study, these differences are mainly in the use of product types, types of meat and the level of moringa plants.

Conclusion
The study showed that the addition of moringa flour extract can reduce the raw pH value, but can maintain the cooked pH value, cooking loss, and water holding capacity.The hedonic quality can also be maintained by adding up to 4% moringa extract flour.The addition of moringa flour extract up to 4% can maintain the physical and hedonic qualities and can be applied to the production of beef patties.

Table 2 .
The physical quality of medium-cooked beef patties supplemented with moringa flour extract at various levels a,b Different superscript in the same row showed significantly different (P<0,01) Noted: C0 = Beef patties compound moringa flour 0% C1 = Beef patties compound moringa flour 2% C2 = Beef patties compound moringa flour 4%

Table 3 .
Hedonics Test of Medium-Cooked Beef Patties supplemented with moringa flour extract at various levels