Improvement of Quality Characteristics and Shelf Life Extension of Raw Chicken Meat by Using Black Mulberry Leaf ( Morus nigra L.) Extracts

. Te objective of this study was to examine the impact of diferent concentrations of black mulberry leaf extract (BMLE) on the microbial quality, lipid oxidation, biogenic amine content, color stability, and sensory attributes of raw chicken meat during a 12-day chilled storage period. Te raw chicken meat was treated with 0.1% BHT (positive control), 0.1%, 0.3%, and 0.5% BMLE, and the outcomes were then compared to the results obtained from raw chicken meat with no additive (control). In comparison to the control group, the inclusion of BMLE resulted in a decrease ( P < 0 . 05) in pH and thiobarbituric acid reactive substances (TBARS), as well as an improvement in redness ( a ∗ ) ( P < 0 . 05). Te addition of BMLE signifcantly extended the shelf life of raw chicken meats compared to the control, as it limited microbiological development and lipid oxidation during storage ( P < 0 . 05). Ad-ditionally, the BMLE exhibited the most potent inhibitory impact on the buildup of these four BAs (tyramine, cadaverine, histamine, and tyramine) in raw chicken samples at the 12-day storage period ( P < 0 . 05). Despite the 0.5% BMLE groups’ lowest results for microbial counts, TBARS, and biogenic amines, the concentration of 0.3% BMLE proved to be the most advantageous in terms of sensory acceptability. Tese fndings suggested that BMLE, rather than artifcial chemicals, could be utilized in raw chicken products as a promising natural antioxidant and antibacterial agent.


Introduction
Poultry meat is one of the most widely consumed foods in the world, and its production and consumption have increased signifcantly in the past several decades.Te appeal of poultry meat stems from the fact that it is the most affordable and readily available meat source, and unlike beef or hog, in terms of culture or religion, there are no restrictions on it [1].Its low-fat content has led to the designation of poultry meat as a low-calorie food.However, because of its high degree of unsaturation, the lipids in its muscles are pretty vulnerable to oxidation.Modern countries prefer poultry due to its accessibility, ease of use in further processed dishes, and healthier profle [2].One of the main reasons meat quality deteriorates is lipid oxidation, which can lead to rancidity and the development of unwanted favors and aromas.Tese efects reduce the functional, sensory, and nutritional value of meat products and their acceptance by consumers [3].Internal factors such as iron content and antioxidant enzymes, along with external factors like feeding with oxidized foods, stress, slaughtering procedures, temperature, additional processing processes, and storage conditions, primarily infuence the oxidation of poultry meat [2].Poultry meat products can spoil due to either chemical deterioration or microbial growth.Te main form of chemical deterioration is oxidative rancidity, which can cause signifcant changes in favor, color, and protein structure and a loss of freshness that may discourage repeat purchases by consumers [4].Synthetic antioxidants, including propyl gallate (PG), butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butyl hydroxyquinone (TBHQ), can be added to poultry meat to delay, lessen, or avoid oxidative degradation [5,6].However, due to the potentially harmful efects of synthetic additives, consumers reacted negatively, prompting producers to turn to natural antioxidant sources [7].In meat and meat products, edible extracts from plants and fruits high in phenolics have recently replaced synthetic substances to slow the oxidation of lipids and proteins, lessen discoloration, and inhibit the growth of microorganisms [8,9].
Black mulberry leaves (Morus nigra L.) have been used as herbal medicines in China since ancient times and have recently become the most popular form of herbal medicine.Te variations in nutritional components of mulberry leaves across diferent studies can be attributed to diferent factors such as varieties, genetics, environments, ecologies, and plant harvest conditions.Research fndings indicated that dried mulberry leaf powder consists of moisture (ranging from 5.11% to 7.24%), crude protein (15.31% to 30.91%), total ash (14.59% to 17.24%), neutral detergent fber (NDF) (27.50% to 36.66%), crude fat (2.09%), carbohydrates (9.70% to 29.74%), and energy content (113 to 224 kcal/100 g).Its bioactive compounds and phenolic substances contribute to its high antioxidant activity.Te black mulberry leaves contain several primary phenolic acids, including cafeic acid, vanillic acid, chlorogenic acid, hydroxybenzoic acid, pcoumaric acid, sinapic acid, and ferulic acid.Furthermore, black mulberry leaves have demonstrated antimicrobial properties [10].Despite these features, there is a signifcant lack of research on the use of black mulberry leaves in poultry meat.Hence, exploring the possible use of black mulberry leaves as a natural source of antioxidants in poultry products is crucial for enhancing their quality properties.So far as we are aware, no study is available to determine how black mulberry leaves afect the qualitative attributes of raw chicken meat.Te objective of the investigation was to assess the impact of diferent concentrations of black mulberry leaf extract (BMLE) on the microbiological quality, lipid oxidation, biogenic amine content, color stability, and sensory attributes of raw chicken meat over a 12-day refrigerated storage period.

Material and Method
2.1.Materials and Chemicals.For this study, armless and skinless chicken thigh fesh was shipped in ice boxes to the laboratory from a nearby poultry meat processing facility (Gedik Pilic Co).

Preparation of Black Mulberry Leaf Extract (BMLE).
Fresh black mulberry leaves (Morus nigra) were collected from diverse locations in Us ¸ak, Turkey, using clean, dry, and sterilized plastic containers.Subsequently, these leaves were dried in the shade at room temperature in the clean, dry laboratory and were fnely ground into a powder with a grinder for 2 minutes.Te resulting powder was stored at −20 °C to prevent enzymatic degradation.Black mulberry leaf extract was extracted following the procedure outlined by Martin-Garcia et al. [11].Approximately 5 grams of black mulberry leaf powder were added to 25 mL of ethanol (96%) and water (50/50, V/V).Te product blend was subjected to ultrasonication at 60 °C for 45 minutes using an ultrasonic water bath (WB11, Daihan Scientifc, Korea).Ten, the mixture was centrifuged and fltered through the Whatman No: 1 flter paper.Te liquid that passed through the flter was concentrated using a rotary evaporator (IKA, HB4 basic; RV 05 basic, Germany) in a vacuum at 40 °C.After that, 20 mL of the condensed extract was put into 90 mmdiameter Petri dishes.Tese dishes were frozen at −40 °C for 24 hours and subsequently subjected to lyophilization at 50 °C.

Analyzing the Characteristics of BMLE.
A pH measurement was conducted using a digital pH meter (Hanna Instruments, pH210, USA).A chromameter (Konica Minolta CR-410 from Osaka, Japan) was used to measure color values.Total phenolic content (TPC) was assessed using the Folin-Ciocalteu method, as detailed by Singleton et al. [12].Te DPPH radical scavenging activity, denoted as DPPH-RSA, was assessed through the methodology outlined by Blois [13] for measuring the capability to neutralize the DPPH (2,2-diphenyl-1-picryl-hydrazyl) radical.

Preparation of Raw Chicken Meat.
To achieve this goal, around 1 kg of chicken thigh meat without skin or bones was soaked in 2 L of distilled water with varying levels of BMLE for 5 minutes, such as control (0% BMLE, without extract), 0.1% BMLE, 0.3% BMLE, and 0.5% BMLE.Te other group dipped in a 0.1% BHT solution.Each piece of chicken meat from the extract solution was drained through a sieve for fve minutes, then placed in polystyrene trays and covered with polyethylene flm.Following packaging, the samples were kept at 4 °C for 12 days, and analyses were conducted on days 0, 3, 6, 9, and 12. Te complete research comprised two independent trials with three measurements for each analysis at distinct manufacturing times.

Analysis of Raw Chicken Meat
2.5.1.Approximate Composition.Te analytical methods indicated by Gökalp et al. [14] were utilized to approximate the chicken fesh samples' ash, moisture, fat, and crude protein content.
2.5.2.pH.About 10 g of chicken meat were combined with 100 mL of distilled water and blended for 25-30 seconds utilizing an ultra-turrax.Te pH levels were carried out at a temperature of about 20 °C using a pH meter (Hanna Instruments, pH210, USA).

Color Analysis.
Te color of the samples was evaluated using a chroma meter (CR-410, Konica Minolta, Osaka, Japan) equipped with an 8 mm-diameter aperture and the standard illuminant D50 at an observed angle of 10 degrees.In the CIE Lab color system, the L * , a * , and b * values correspond to black-white, red-green, and yellow-blue color characteristics, respectively.Te L * value denotes the 2 Journal of Food Quality lightness ranging from black to white, the a * value indicates the presence of red or green hues, and the b * value represents the degree of yellowness or blueness in the color.Te white standard plate was used to calibrate the instrument before color readings were taken.
2.5.4.Microbiological Analyses.Samples weighing ten grams of chicken meat were extracted from each pack and placed in an aseptic stomacher pouch.Te samples were then homogenized using a stomacher for 90 seconds after adding 90 mL of pepton water.Following the decimal homogenate dilutions, a duplicate plate was constructed to count the microbes for each dilution using the surface spreading method.Petri plates were then incubated under aerobic conditions at 30 °C for 2-3 days for total mesophilic aerobic bacteria (TMAB) and at 10 °C for 5-7 days for total psychrotrophic aerobic bacteria (TPAB).After being cultured on MRS (de Man-Rogosa-Sharpe) and VRBD (Violet red bile dextrose) agars for three days at 30 °C, respectively, lactic acid bacteria (LAB) and Enterobacteriaceae were enumerated.Colony-forming units, or log CFU, were used to express the results per gram of sample [15].

Determination of 2-Tiobarbituric Acid Reactive Compounds (TBARS).
Te spectrophotometric technique calculated the samples' TBARS values [16,17].Samples were taken from both the surface and interior for TBARS analysis.Two grams of homogenized samples were double-extracted using 10 mL of 0.4 M perchloric acid each time.Te volume of extracts was completed to 25 mL with 0.4 M perchloric acid, followed by centrifugation (1790 × g for 5 min) (LAB 312 R, TD5, Turkey).Subsequently, 1 mL of the supernatant was transferred to a test tube with a glass stopper, and 5 mL of TBA reagent was added.Te supernatant was then heated in a boiling water bath for 35 min.After cooling, the absorbance was measured at 538 nm (Spektrofotometre, Biochrom, Libra S70, England).Te calibration curve was established using 1, 1, 3, 3-tetraethoxypropane (TEP).
2.5.6.Biogenic Amine Analyses.Te determination of BA content was conducted using the HPLC chromatographic method, following the method outlined by Bulut et al. [18] and Çelebi et al. [17] with some adjustments.Two grams of chicken meat were treated with 25 mL of 0.4 M perchloric acid and centrifuged (LAB 312 R, TD5, Turkey) at 1500 × g for 5 min.Ten, 1 mL of the supernatant was alkalized using 200 μL of 2 N NaOH; 300 μL of saturated sodium bicarbonate was added as a bufer. 2 mL of dansyl chloride solution was then added, and the sample was incubated at 40 °C for 75 min.100 μL of 25% ammonia was added to suspend the residual dansyl chloride.After 30 min of incubation at room temperature, the sample was diluted to 5 mL with acetonitrile and then centrifuged at 1500 × g for 5 min.Te supernatant was fltered through a sterile microflter (0.45 μL).A gradient elution program was employed with mobile phases of acetonitrile (solvent A) and 0.4 M ammonium formate (solvent B), starting at 50% solvent A and 50% solvent B and concluding at 90% solvent A and 10% solvent B after 20 min.Te temperature of the column was 40 °C, and the fow rate was 1 mL/min −1 .

Sensory Analysis.
All samples were prepared by cooking them in a heated oven at 175 °C until the internal temperature of the meat samples reached roughly 70 °C.Te panelists were allowed to evaluate a range of attributes of the cooked chicken meats, including color, smell, favor, texture, and overall acceptability, using a hedonic scale ranging from 9 to 1 (with 9 representing extreme liking, 5 representing moderate liking, and 1 representing dislike).Te panelists were provided with water and a galette between samples to cleanse their palates and remove residual favors [19].Ten pre-informed and trained panelists carried out the sensory evaluation of chicken meats.

Statistical Analysis.
Te data of analyses were evaluated using the SPSS-20 (Armonk, NY, USA) package program.pH, color, TBARS, BAs, and microbiological counts data were subjected to multivariate analysis of variance (MAN-OVA) using the general linear model (GLM).Duncan's multiple comparison test was used to determine whether there were diferences between the groups.Additionally, the results of BAs were treated with GraphPad Prism 10 Software, and the signifcance levels were indicated as * P < 0.05, * * P < 0.01, and * * * P < 0.001.

BMLE's Physicochemical Characteristics and Antioxidant
Capacity.Table 1 lists a few of the physicochemical (pH, L * , a * , b * ) and antioxidant potential characteristics (TAC, TPC, TFC, DPPH-RSA) of BMLE.Te phenolic compounds found in MLs can difer depending on factors such as variety, how they are grown, how long they are allowed to mature, and how they are processed [20].Our fndings are similar to the TPC (0.54-0.76 mg GAE/g) and TFC (105.33-143.94mg QE/g) reported by Bülbül [21].Te physicochemical and antioxidant results of BMLE (Table 1) are consistent with information found in the literature about black mulberry leaves [22].Te primary naturally occurring active component of mulberry leaves (MLs) is polyphenol, an extremely potent antioxidant that may scavenge free radicals of oxygen, hydrogen peroxide, hydroxyl, etc [20].Tese results suggest that BMLE may be a good source of antioxidants for fresh poultry items susceptible to oxidative processes that cause rancidity and discoloration.

Approximate Composition of Raw Chicken Meat.
Table 2 displays the approximate composition (moisture, protein, ash, and fat) of chicken meat products containing varying amounts of BMLE (0.1%, 0.3%, and 0.5%) and BHT (0.1%).Te moisture, fat, protein, and ash values of the raw chicken meat samples were not signifcantly afected by the BMLE application (P > 0.05).

pH and Color Parameters of Poultry Meat.
Te pH levels of raw chicken meat indicate no statistical diference (P > 0.05) (Table 3) in the A * S interaction.Te pH levels of all raw chicken meats applied with BMLE were lower than those of the control samples, with a signifcance level of P < 0.05 (Table 4).Tis drop could be explained by BMLE's average pH value of 4.88 (Table 1).Te pH levels of the raw chicken meats rose during storage, with the most notable rises occurring in the control group (Table 4).Turan and S ¸ims ¸ek [23] found that throughout the storage period, the pH of beef patties with Morus nigra leaf extract progressively increased in all samples.After storage, the pH values of the 0.1%, 0.3%, and 0.5% BMLE groups were 0.31, 0.40, and 0.46 units lower than those of the control samples.Te rise in pH levels in stored samples results from bacterial activity in meat, leading to the accumulation of microbial by products.When stored glucose is depleted, bacteria consume the amino acids generated during the breakdown of proteins, and ammonia from the breakdown of amino acids builds up and raises pH [24].Te presence of large quantities of Enterobacteriaceae microorganisms with proteolytic activity can also contribute to higher pH levels in meats [25].Te incorporation of BMLE had no efect (P > 0.05) on the L * levels of samples at storage days (Table 4).Te study by Zhang et al. [22] yielded similar fndings to our research, as they also observed no discernible trend in the changes of L * and b * values in the color of raw ground beef when treated with mulberry leaf extracts and stored in refrigeration.However, the L * levels of raw chicken meats signifcantly decreased (P < 0.05) during storage.Adding BMLE made the thighs slightly darker, leading to lower L * values (Table 4).Lower L * values during storage may be caused by the dipping solution containing BMLE, which has naturally occurring dark color pigments and a darker hue than the purifed water and 0.1% BHT used in the control groups.Several studies have demonstrated that the inclusion of natural antioxidants led to a decrease in the L * values of chicken meat samples [26,27].According to Turan and S ¸ims ¸ek [23]; using black mulberry water extract in packaging beef patties can decrease their lightness values.Te extract's initial color values and high anthocyanin content are believed to cause this change.Te a * levels of the chicken meats were not signifcantly diferent on days 0, 3, 6, and 9.However, on day 12, a statistically signifcant diference was observed in redness between the samples (Table 4).Myoglobin oxidation caused a reduction in the a * values of all treatments from day 0 to day 3. Iron atoms can oxidize or denature myoglobin molecules during oxidation, which results in a negative color change in the products and the conversion of myoglobin to methemoglobin [26].Troughout storage, the TBARS levels of the groups in this investigation rose, correlated with decreasing a * values, consistent with other studies in the literature [26,28].Following the storage time, the control samples showed the lowest a * value, whereas the 0.5% BMLE samples showed the greatest a * value.At the end of storage (day 12), the order of a * values was as follows: 0.5% BMLE > 0.3% BMLE > 0.1% BMLE > 0.1% BHT > Control.Tese fndings suggest that the extracts successfully maintained the red color of the meat.Turan and S ¸ims ¸ek [23] observed that beef patties with 0.2% black mulberry water extract had increased a * compared to the control group.Additionally, the patties treated with 0.2% extract had higher a * values than those treated with 0.4% after being stored aerobically for 15 days.Additionally, Zhang et al. [22] stated that the incorporation of mulberry leaf extracts caused a decrease in the a * values of unprocessed ground beef.In the current investigation, yellowness (b * ) was found to be signifcantly infuenced (P < 0.001) by A * S interaction (Table 3).Te yellowness values of chicken samples on days 0, 3, and 9 were not statistically (P > 0.05) diferent.Nevertheless, there were notable variations between the treatments on the remaining days (P < 0.05).b * values of samples are infuenced diferentially by the extracts' color, which might vary from light green to dark yellow.Te storage had a notable impact (P < 0.05) on the b * values of the treatments except for the % 0.5 BMLE group.Generally, the b * values of all samples  4 Journal of Food Quality fuctuated throughout the storage.At the end of storage, the b * values of the control and BHTgroups increased compared to their initial values.However, there was a notable difference in the yellowness of the samples with BMLE addition (P < 0.05).Te use of BMLE in this study resulted in a decrease in the b * values of chicken meat compared to control groups by the end of the storage period.Tese fndings indicate that BMLE had a noticeable impact on the yellowness.In this study, the preservation of desired color parameters of chicken meat during chilled storage was achieved by BMLE.Te reason for the enhancement in color values compared to the control can be attributed to its high amount of antioxidants and low pH level.

Microbial Counts of Raw Chicken Meats.
Te results presented in Table 3 demonstrate that the interaction of A * S had signifcant P < 0.05, P < 0.001, and P < 0.05 efects on the counts of TMAB, TPAB, and Enterobacteriaceae in raw chicken meat products, respectively.Te variations in microbial counts that occur when chicken meats are stored, both with and without BMLE, are displayed in Figures 1(a)-1(d).No diferences in TMAB numbers as of day 0 were observed among the control, 0.1%, 0.3%, 0.5% BMLE, and 0.1% BHT treatments (P > 0.05) (Figure 1(a)).Te TMAB and TPAB counts of chicken meats with BMLE added were considerably (P < 0.05) lower than those of the control groups (Figures 1(a) and 1(b)).During the storage period, there was a continuous increase in the TMAB levels of chicken meats.It was found that the control groups (7.46 log CFU/g) and 0.1% BHT incorporated groups (7.25 log CFU/ g) surpassed the limit value on day 9 in chicken meats (Figure 1(a)).Additionally, the TMAB counts of the BMLE and BHT-added chicken meats stayed within acceptable limits throughout the 9-day storage period (Figure 1(a)).Te shelf life of raw chicken meats stored aerobically in refrigerated conditions is approximately 5 days, based on conditions for hygiene and preservation [29].Te current investigation showed a signifcant increase (P < 0.05) in TPAB counts as the storage time increased.Te chicken  Te LAB proliferation of chicken meats was promoted by the addition of BMLE, and this efect depended on the level of extract on day 12 of storage (P < 0.05).Te groups containing 0.3% and 0.5% BMLE, respectively, had the highest LAB number (P < 0.05) at the end of storage (Figure 1(c)).Te promotion of LAB development by BMLE was likely due to its ability to reduce pH and the potential stimulating impact of its components on LAB [23].Despite initial counts ranging from 1.88 to 1.92 log CFU/g, there were no signifcant diferences (P > 0.05) in Enterobacteriaceae numbers on day 0 across all treatments studied.Te counts of Enterobacteriaceae signifcantly increased (P < 0.05) during storage.Chicken meat with 0.5% BMLE had the lowest counts (P < 0.05) (Figure 1(d)).Turan and S ¸ims ¸ek [23] found that the initial levels of Enterobacteriaceae in aerobically packaged beef patties, whether or not lyophilized black mulberry water extract was applied, were between 2.43 and 2.52 log CFU/g.Tey also observed that the increasing number of Enterobacteriaceae in control groups (from 2.52 to 5.01) was higher than in groups with 0.4% BMWE extract (from 2.45 to 4.91) over a 15-day storage period.Te inclusion of BMLE in samples resulted in a signifcant LAB (log cfu/g) Enterobacteriaceae (log cfu/g) 3 day 6 day 9 day 12 day 0 Day

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Journal of Food Quality (P < 0.05) decrease in microbial numbers (apart from LAB), indicating that BMLE positively afected the shelf life and microbial quality of chicken meat.

Lipid Oxidation.
Te quantity of secondary lipid oxidation products, mostly aldehydes (or carbonyls), that give oxidized meat and meat products an unpleasant favor is represented by the TBARS values.Te degree of lipid oxidation in meat samples during storage can be monitored using these measurements [30].Te results presented in Table 3 indicate that A * S interactions had an important (P < 0.001) impact on the TBARS levels of chicken meats.
Including BMLE in chicken meat resulted in a benefcial impact on reducing TBARS levels (Figure 2).Te chicken meat with BMLE exhibited a noticeably (P < 0.05) reduced TBARS content compared to the control groups.Te progressive rise in TBARS values over time is consistent with previous research fndings that suggest an increasing formation of TBARS during storage [22,23,26].Te fndings from chicken meat in Figure 2 demonstrate that TBARS values in the control group reached threshold values (<1 mg/ kg) on the sixth day.Tere were values exceeding the limit on day 9 in the groups with 0.1% BMLE (1.12 mg/kg), 0.3% BMLE (1.00 mg/kg), and 0.1% BHT (1.24 mg/kg) (P < 0.05).However, the TBARS value of the 0.5% BMLE group was 1.21 mg/kg and exceeded the threshold value on day 12 (P < 0.001) (Figure 2).As a result, it was discovered that the application of 0.1-0.3% and 0.5% BMLE led to a delay in chicken meat lipid oxidation by 3 and 6 storage days, respectively, compared to the control groups.Te TBARS values of chicken meat on day 12, which were incorporated with 0.1%, 0.3%, or 0.5% BMLE and 0.1% BHT, were 43.22%, 54.16%, 83.47%, and 18.08% lower (P < 0.001), respectively, compared to the control sample (Figure 2).Tese fndings suggest that BMLE may be a natural antioxidant to prevent lipid oxidation rather than synthetic antioxidants.Furthermore, it was discovered that 0.5% BMLE was superior to 0.1% and 0.3% BMLE in both packing techniques for postponing lipid oxidation.Tis extract's substantial phenolic and antioxidant content is responsible for BMLE's preventive activity against lipid oxidation.Phenolic compounds exhibit vigorous antioxidant activity using mechanisms such as transition-free radical scavenging activity and single-oxygen quenching capacity [31].According to Turan and S ¸ims ¸ek [23], the beef patties infused with black mulberry water extract exhibited lower and more consistent TBARS levels throughout the 15-day storage duration compared to the control group.In the same way, mulberry leaf extracts reduced the TBARS level of ground beef compared to the control sample [22].
3.6.Biogenic Amine Analysis.Te high amount of protein in poultry meat leads to an increased breakdown of proteins and the release of amino acids.Tis, along with the presence of bacteria that can break down amino acids, speeds up the spoilage of meat and leads to higher levels of substances produced by microorganisms, such as biogenic amines [32].Six biogenic amines (Bas)-cadaverine, putrescine, tyramine, histamine, spermine, and spermidine-were found and measured during storage.Te results presented in Table 3 indicate that A * S interactions had an important (P < 0.001) impact on the histamine, tyramine, cadaverine, and putrescine levels of chicken meats.Additionally, Bas (without spermine and spermidine) in the samples with and without BMLE increased at the end of storage (P < 0.05) (Figure 3).However, spermine and spermidine, crucial for cell division and growth, remained unafected (P > 0.05) by storage conditions, unlike the other biogenic amines analyzed in all samples.Notably, in addition to their role in cellular processes, spermine and spermidine also serve as a nitrogen source for bacteria [33].Te levels of spermine and spermidine vary between 12.80 and 13.30 mg/kg and  [34], consuming too much putrescine might increase the toxicity of histamine and tyramine, in addition to causing poisoning.As seen in Figure 3(d), the putrescine in the control groups grew more quickly than in the other treatments, reaching 20.79 mg/kg at the end of storage (P < 0.05; P < 0.01; P < 0.001).Te addition of BMLE may inhibit putrescine accumulation, notably 0.5% BMLE, which at 12 days signifcantly decreased putrescine production by 32.65% (P < 0.001) compared to the control.Te most harmful BA found in food is histamine, which, when consumed in excess, might result in symptoms including headaches and diarrhea [35,36].Histamine formation was not observed in all samples at the beginning of storage, and their formation increased to 4.55, 3.11, 3.00, 2.79, and 3.90 mg/kg at 12 days for the control and samples with 0.1% BMLE, 0.3% BMLE, 0.5% BMLE, and 0.1% BHT, respectively (P < 0.01, Figure 3(e)).BMLE exhibited efective inhibition of histamine.Te histamine content in chicken meats with 0.5% BMLE was 34.06% lower than that of the control (P < 0.0001) at 12 days (Figure 3(e)).Te changes in the contents of tyramine exhibited a similar pattern, as indicated in Figure 3(f ).Te levels of these substances were signifcantly higher in the control groups compared to the samples treated with BMLE and BHT at the end of storage (P < 0.05).Additionally, the group treated with BMLE demonstrated the greatest inhibition (P < 0.0001).Te BMLE exhibited the most potent inhibitory impact on the buildup of these four BAs in raw chicken samples at the end of storage.Tis could be due to its ability to suppress the growth of TMAB, TPAB, and Enterobacteriaceae (BApositive bacteria) in chicken meats, as demonstrated in Figure 2

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Journal of Food Quality uncontrolled microbial enzymatic activity.On the other hand, it is believed that the BMLE group, having a higher lactic acid bacteria (LAB) count, can suppress the formation of biogenic amines (BAs).
3.7.Sensory Analyses.Figure 4 displays the sensory scores of the cooked chicken samples on day 5.No signifcant differences (P > 0.05) existed between the control and BMLEadded chicken meats, even though favor scores were highest in the 0.3% BMLE-added chicken meats.Te color and texture of cooked chicken meats were enhanced (P < 0.05) by adding 0.3% BMLE.Te control groups and those with 0.1%, 0.3%, and 0.5% BMLE's smell scores were not statistically signifcant (P > 0.05).Similarly, Turan and S ¸ims ¸ek [23] showed that the addition of 0.1% and 0.2% black mulberry water extract did not impact the color, texture, smell, and favor ratings of cooked beef patties.Te samples Figure 3: Biogenic amine levels of raw chicken meat groups at the end of cold storage (mg/kg).ns: not signifcant, * P < 0 .05,* * P < 0 .01,* * * P < 0.001, * * * * P < 0.0001.Journal of Food Quality with 0.3% BMLE added had the highest overall acceptance scores for cooked chicken meats (P < 0.05).Te addition of 0.3% BMLE can be regarded as the most appropriate quantity to avoid adversely afecting the sensory qualities of cooked chicken meats, taking into account all sensory features that have been studied.However, the results for lipid oxidation and microbial count indicated a more favorable efect with 0.5% BMLE.So, the suggested recommendation is to utilize 0.5% black mulberry leaf extract (BMLE) for raw meat preservation.

Conclusion
Te fndings suggest that incorporating BMLE signifcantly enhances the microbial quality, lipid oxidation, biogenic amine content, color stability, and sensory properties of chicken meat.Te results demonstrate a substantial enhancement in microbial quality, lipid stability, and color retention, particularly at specifc concentrations of BMLE.Additionally, the extract exhibits inhibitory efects on biogenic amine accumulation, contributing to raw chicken meat's overall freshness and safety.Tese outcomes underscore the potential of black mulberry leaf extract as a valuable natural ingredient for raw chicken products during refrigerated storage, preserving and enhancing their overall quality.Additionally, the application of BMLE is recommended not only for enhancing the quality of raw chicken meat but also for improving processed chicken products such as nuggets, schnitzel, and chicken patties.

Figure 1 :
Figure 1: Microbial counts of raw chicken meat groups during cold storage (log CFU/g).Bar charts with diferent letters (a-d) and (A-D) indicate signifcant diferences between treatments and storage days, respectively (P < 0.05, Duncan's test).

Figure 4 :
Figure 4: Sensory evaluation of cooked chicken meat samples.

Table 2 :
Approximate composition of raw chicken meat samples.

Table 3 :
Te efects of application (A), storage day (S), and correlation of A * S on pH, TBARS, color, biogenic amine values, and microbial counts of raw chicken meats.

Table 4 :
pH and color values of raw chicken samples during chilled storage.
Figure 2: TBARS levels of raw chicken meat groups during cold storage (mg/kg).Bar charts with diferent letters (a-d) and (A-E) indicate signifcant diferences between treatments and storage days, respectively (P < 0.05, Duncan's test).