ADDITION OF BANANA PEEL FLOUR

Banana and plantain constitute the fourth most important staple food commodity in the world, after rice, wheat and maize (Islam et al., 2016). Since researchers started focusing on studying the composition of banana peel, several possible applications have emerged (Agama-Acevedo et al., 2016). Due to the presence of these compounds, bananas have a higher antioxidant capacity than some berries, herbs and vegetables (Moongngarm et al., 2014).

In general, banana peel has been reported to contain more DF than banana pulp (Garcia-Amezquita et al., 2018). Several studies have reported the use of banana peel flour (BPF) as a functional food source (Ramli et al., 2010). According to some reports, both pulp and peel have high antioxidant activity (Gonza ´lez-Montelongo et al., 2010).

Table 4.1 : Chemical composition of BPF bread 33 Table 4.2 : Chemical composition of Control Cake and formulated cake

Review of Literature

Banana

Medicinal Importance of Banana and its Peel .1 Reduced risk of high blood pressure

Restore normal bowel Activity
Cholesterol-lowering effect
Kidney Health
Energy Booster
Immunity Booster
Heart health
Digestion and weight loss
Vision
Bones
Cancer
Health effects of banana bioactive compounds

A flavonoid in bananas, leucocyanidin, has been found to significantly increase the thickness of the stomach lining. A normal intake of potassium suppresses the excretion of calcium in the urine and minimizes the risk of kidney stones. Recently, it has been shown that gallocatechol extracted from GBPe was effective in healing surgical wounds in mice (Von Atzingen et al., 2015).

Accordingly, a unique flavonoid called leucocyanidin was found in the aqueous extract of the pulp of unripe plantains, which is now known to be effective in the treatment of stomach diseases (Lewis et al., 1999).

Health benefits of phenolics

Catecholamines, dopamine, norepinephrine (noradrenaline) and epinephrine (adrenaline) are the best known examples of these bioactive compounds that regulate hormones in glycogen metabolism (Gonza. ´lezMontelongo et al., 2010). Banana peel is said to be rich in many high-value antioxidant phytochemicals that promote health, such as anthocyanins, delphinidin, and cyanidins (Seymour, 1993). In a recent study, Rebello et al. 2014) also showed that banana peel extract is a rich source of total phenolics (29 mg/g as GAE), which are responsible for very high antioxidant activity.

Banana flour applications

Bread
Cake

While TDF and ash content increased significantly in 20% substitution, they were the significant technological defects (Gomes et al., 2016). In a study on gluten-added bread, substitution of 25% of finished freeze-dried banana powder (ripening level was not mentioned) with wheat flour resulted in increased volume and viscosity of leavened bread (Mohamed et al., 2010). Regarding the evaluation of shelf life, while bread aging (firmness) increased in higher BF concentration regardless of storage temperature (25 C, 4 C and - 20 C), the stiffness of the control was higher than BF bread (Mohamed et al., 2010 ).

By comparing the storage temperature, it was found that bread stored at -20 C for up to 7 days was less hard compared to other samples (Mohamed et al., 2010). Similar findings were reported by (Ho et al., 2013) who prepared steamed bread with 30% GBPF wheat flour substitute. Despite the high concentration of sugar, the premix remained quite unchanged in terms of pH and pathogenic growth, fungi or yeasts (Borges et al., 2010).

The reason behind this phenomenon was the lower amount of moisture content in banana cakes (Park et al., 2010). Researchers showed that the fine flour comprised 40% RS compared to 25% RS in the coarse flour. However, the percentage of TDF, protein, ash, lipid, phenolic compounds and amylose was higher in the coarse flour.

Nevertheless, samples made of fine particle sizes of GBPF showed better nutritional properties without adversely affecting textural properties (Segundo et al., 2017a). Considering that the relationship between volume and firmness was more significant in mushrooms than in layer cakes, banana ripeness was not correlated to improvements in textural properties (Segundo et al., 2017b).

Introduction

Sources of ingredients of Cake, Bread, Jam

Processing of Banana into Powder form

Blend formation and Bread making
Preparation of Cake

Three bread samples were prepared, one sample was considered as control and others were considered as banana peel flour (BPF) treated sample. The ratio of whole wheat flour to banana and peel flour in different samples was as follows: 100:0 (control sample), 90:10 and 85:15 (treated samples). The dough was then fermented in a bowl covered with sterile wet clean muslin cloth for 1 hour at 29℃.

The fermented dough rose to twice its original volume by trapping air during this period. The risen dough was then punched to remove air and scaled into 350 g dough pieces. This weighed dough was formed into its final form into bread-making cubes and tested in a manually prepared proofing cabinet for one hour at 30℃ maintaining 85% relative humidity.

Two cakes were prepared, one control and other was formulated with Banana with peel flour (BPF). Cake was prepared by replacing wheat flour with different levels of Banana peel flour in the basic formulation of cake according to the methods of Rajchel et al. All-purpose flour, banana peel flour and other ingredients for each cake were accurately weighed, and the sugar and shortening were mixed in a mixer for 20 minutes to produce a cream.

Jam formulation from 50 g of powdered stevia leaf extract and 1 g of citric acid and 30 g of banana peel powder (BPP). Sugar previously dissolved in boiling water with citric acid was added to the BPP (pectin extract) dispersion after heating at 121℃ for 20 minutes. The dispersion was then reheated for approximately 30 minutes at 80℃. In order to obtain the desired gel consistency, the end point was estimated as the point at which the total soluble solids of the viscous dispersion reached 72 °Bx as determined by a handheld refractometer.

Proximate Analysis

Crude Protein determination
Crude Fat Determination
Crude Fiber Estimation
Estimation of Ash

Distilled water 60 ml was added to BPP in a water bath for 10 min to extract the pectin. The dispersion was then poured into a mold and cooled for 48 hours at room temperature to produce a block. The moisture content was determined using the procedure as follows: 2 g of the ground sample was weighed using an analytical balance, placed in a jar and dried in a thermostatically controlled oven at 105℃ for 5 hours.

Approx. 10 ml of 4% boric acid with 3 drops of green bromocresol indicator was prepared as receiving solution in conical flask. Then, 25 mL of 40% NaOH was automatically filled into the tube and the distillation process was carried out for 4 minutes. After that, boiling for 20 minutes, rinsing for 20 minutes and evaporation were carried out in the chamber and finally the percentage of fat in the sample was calculated.

This method performs the oxidation of all organic matter by incineration and determines the weight of the remaining ash. Then we put exactly 2-5 g of samples in a crucible and burned the samples in the crucible so that there was no smoke.

Figure 3.5: Crude protein determination.

Sensory Analysis

Microbiological Analysis Determination of total bacterial count

Antioxidant activity

Preparation of DPPH solution (100 μm)
Preparation of standard ascorbic acid solution
Procedure
Total flavonoid content determination

Preparation of 1M potassium acetate solution 0.9815 g of potassium acetate was dissolved in 10 ml water

Preparation of 10% AlCl 3 solution 1gm AlCL 3 was dissolved in 10ml water

Preparation of standard quercetin solution

Serial dilution was then performed to prepare different concentrated solutions (2 ppm, 4 ppm, 8 ppm, 16 ppm, 32 ppm). The content of total phenol in sample extracts was evaluated using the Folin-ciocalteu method as described in (Wojdyło et al., 2007). Approximately 1 ml of samples or standard extracts at different concentrations were mixed with 2 ml of Folin-Ciocalteu reagent (10-fold dilution) and incubated at room temperature for 3 minutes.

Then, 10 ml of 20% sodium carbonate was added to the mixture and incubated for one hour at room temperature. The absorbance of the mixture was measured at 765 nm with a Shimadzu UV-VIS-2600 spectrophotometer against a blank solution. The gallic acid standard curve was used to quantify total phenolic content and results were expressed as mg gallic acid equivalent (GAE) per gram dried weight.

Then, serial dilution was performed to prepare different concentrated solution (6 ppm, 12 ppm, 24 ppm, 48 ppm, 96 ppm). About 1 ml of sample or standard solution with different concentrations was taken in a test tube. The reaction mixture was then incubated for 30 minutes at room temperature to complete the reaction.

The calculation of the total content of flavonoids in the extracts was performed in triplicate and the results were averaged. The final result was expressed as mg quercetin equivalent (QE) per grams dry weight.

Figure 3.10: samples preparation and UV-visible spectrography analysis of flavonoid and phenolic compounds

Statistical Analysis

Results 4.1. Proximate composition

It was observed that protein and fat content decreased with increasing levels of substitution while ash and crude fiber content increased. There was significant difference (p<0.05) in crude fat, crude fiber and ash content between formulated BPF.

Proximate Analysis of Cake

Formulated Jam

Banana with peel flour jam is specially prepared for obese and diabetic patients, containing no added sugar and artificial pectin. There was a significant difference (p<0.05) in crude fiber between formulated jam with BPF and the controlled banana jam.

Sensory Evaluation

Antioxidants Activity

Contents of total phenolics
Total Flavonoid Content

The total flavonoid content in Banana with peel flour (BPF), BPF-formulated bread-1, BPF-formulated bread-2, BPF-formulated cake, control cake and BPF jam is described in table 4.

Standard curve of Gallic Acid

Antioxidants Activities of Products
of Value of Different products

Microbiological Analysis

Discussion

The proximate analysis
Microbiological analysis
Sensory analysis
Antioxidants analysis

Conclusion

The proximate composition of the treatment BPF bread samples and control samples is shown in Table 4.1. Regarding ash content, higher ash content was observed in the banana with peel flour bread1 and bread2 with mean value 2.25% and 3.01% where the control had mean value 1.7% respectively. The protein content of the control and the banana peel flour substituted samples were 9.2 and 9.2 respectively.

The results of the sensory evaluation of bread prepared from banana peel flour (BPF) are presented in table 4.4. The mean values of the individual attributes from the sensory evaluation indicate that the panelists liked the products. The average values of the overall acceptability of the samples showed that there was no significant difference (p>0.05) between the two formulated samples.

The sensory evaluation of jam shown in Table 4.6, the results indicated that the panelist scored the product in the overall acceptability parameter was 4.5, which means neither liked nor disliked the product. DPPH free radical scavenging activities of BPF, BPF bread, BPF jam and BPF cake were shown in Figure 4.7. Sensory evaluation showed that banana with peel flour bread-2 (15%) was more preferred compared to BPF bread-1 (10%).

The proximate composition of BPF bread-2 and BPF formulated cake had significantly (p<0.05) higher moisture, protein, ash and fiber contents. The findings of the study show that banana flour products with peel are a good source of fiber, ash, protein and CHO.