Chemical and Technological Studies on Mango Seed Kernels for Enhancing the Organoliptic and keeping quality of one bakery products.

Introduction

Mango is one of the most popular, delicious and nutritive fruit. Therefore, huge amounts of mango seeds are discarded as wastes. Thus , many efforts have to do as means to overcome the resultant pollutions of these wastes. Mango seed kernels represents from 10 to 25% of the whole fruit weight (Helmavathy et al.,1988). The kernels inside the seed represent from 45 to 75% of the whole seed and about 20% of the whole fruit (Arogba, 1997). However, more than 32,7000 ton of mango fruit were produced in 2004 (FAO,2004).Depending on there varity, mango seed kernels contain 6.0% protein,11%fat,77%carbohydrates,2.0% crude fibers and 2.0%ash (Zein et al.,(2005). The lipids of mango seed kernel consists of about 44-48% saturated fatty acids and the majority was stearic.52-56%were unsaturated and the majority was oleic.(Mohamed & Girgis,2005).

Many studies have reported that mango seed kernels have the antioxidant and antimicrobial activities (Parmar & Sharma,(1986) and Abdalla et al., (2007). Mango seed kernels were shown to be a good source of polyphenols, phytosterols such as campsterol, Β-sitsterol and tocopherols (Soong, et al.,2004).The chemical analyses showed that Mango Kernel Extract (MKE) contained 79.5% polyphenols (Kabuki, et al.,(2000) Mango seed kernels ethanol extract (MKE) showed an antimicrobial activity against both gram-positive and gram- negative bacteria except for Lactic acid bacteria (LAB) at 2500 ppm. Among these pathogens were E. coli, Campylobacter jujoni Yarsinia enterocolitica ,Staphylococcus aurous, Bacillussp Clostridium sp. and Listeria monocytogenes.                                                                                                     

The present study presents some chemical, nutritional, anti- nutritional and antimicrobial characteristics of mango seed kernel flour as a promising by -product and the ability to use it in incorporating with the wheat flour  in an attempt to enhance some physicochemical properties  and shelf life of one bakery products such as pizza base loaf to get rid of this  by- product that cause a huge pollution  and in the same time to achieve a highly benefit in overcoming the malnutrition risk in nutrients in undeveloped countries.                                                                        

Materials and Methods

Ingredients:

wheat flour (72% extraction)was obtained from  North Cairo MillsCompany. Mango seeds were obtained from a big shop making fresh fruit juices in Cairo. Fresh hen eggs , corn oil , butter , sugar and yeast were obtained from local market in Tanta city.

Methods:

Preparing mango seed kernels(MSK) Manually the hasting were done  to remove the hard seed coat from the kernels. Some of mango seed kernels were soaked in distilled water for 72 hr. The soaking water was changed twice daily. The soaked kernels were partially grinded in a wooden mortal and then were dried in sun ,then grinded to a powder form using a blender.                                                                               

Preparing of pizza dough:                                                                        

          Salt and sugar are dissolved in a little amount of worm mixing water. The compressed baker^'s yeast was also dissolved in a little amount warm water ,butter and oils were combined with the whole eggs and the sifted wheat flour and then the other ingredients were added asin the illustrated ratios in table (1) according to Khater &Hellal (2002).Mixing  tab water was added for the control and the treatments by the amounts illustrated in the above table. The combined ingredients were knead (hand mixed) for 5 minute, until stretchened or giving best dough texture, then let rest in a warm place for an hour for leavening. The leavened dough was classified into  equaled balls and let for further leaven for half an hour, then rolled and left for anther 30 min. at room temperature. The rolled dough were baked in a baking oven at 250⁰ C for 5-6 minutes. The produced pizza loaves were packaged in clean polyethylene sucks and tested for shelf-life at both room temp. and at the refrigerator.                   

Table (1):  The formula of  the pizza base dough for  the control  and the treatments(g)/100g.                                                             

Organoliptic  evaluation,

The baked  loaves  were evaluated for  eating quality, the  crumb color, crust character and grain and texture by 8 panelistsaccording to El- Nemr, (1976) with some modifications

Chemical analyses:

          The sun dried mango seed kernel flour. Wheat flour and whole eggs were analyzed for moisture, crude fibers and crude protein according to the AOAC  (1995), while the fat contents was determined according to Folich et al., (1957), but the reducing sugars determined according to Holme &Peck (1983). Fatty acids were determined according to Radwan, (1978) using GC Model,Shimadzu-8A,equipped with FID detector and glass column2.5mX3mmi.d. The amino acidsdetermined according to  Moore& Stain, (1958) . Seeds flour was also analyzed for some mineral content by the atomic absorption (ca, fe, zn, and k) according to Ronald and Ronald (1981), The ant-nutritional factors (tannins and phytic acid) were also measured according to Burns(1971)    and Camire & Clydesdale(1982) respectively. Caroteinoids were determined by HPLC Method according to David and John Scott (1995).Riboflavin also was determined according to Soledad et al.,(1997).

Results and Discussion

Table (2 ) revealed the gross chemical composition of mango seed kernel flour before and after soaking. and also of wheat flour. The obtained data illustrate the richness of protein, fat, crude fibers and ash in MSK compared to wheat flour 72% extraction that increase the nutritional value in the produced bakery product and enhance the organoliptic quality up to certain replacement of wheat flour. These results were in  general in an agreement with those of Zein et al., (2005) and Ahmed et al.,(2007), with the exception of fat and ash that showed a bit little value compared to their results.

Table(2): Gross chemical composition of mango seed kernel flour and wheat flour(gm/100gm)

Table (3) illustrates mango seed kernel contents of riboflavin and carotenes after soaking in distilled water based on wet weight  and some minerals (zn, Fe, K and Ca) based on dry weight. Resultant data showed that mango seed kernel is a good source  of B–carotenes, riboflavin  zinc, iron, potassium and calcium.

Table (3): Mango seed kernel contents of riboflavin and carotenes and some minerals.

*Based on wet weight.  ** Based on wet dry weight

*** source: Bessar et al., (2008)

Anti nutritional factors (tannins and phytic acid) contained in mango seed kernel were given in table (4). The results showed that although mango seed kernel flour contains considerable amounts of these factors, soaking in water reduces it to  the safe level hence the soaking reduces tannins from 4.65 to only 0.65% ( by 4.00%) and phytic acid from 3.80 to 1.93% (by 1.07%) respectively. These results were nearly in agreement with those of Zein et al., (2005).

Table (4): The effect of soaking on the  anti nutritional factors (phytic acid and tannins) content in mango seed kernel        

*Source: Besaar et al.,(2008)

       Data in table (5) presented the fractionation of  fatty acids content of mango seed kernel.These results showed that the main saturated fatty acid was stearic acid (38.337%) before soaking and 36.801% after soaking. At the same time the main unsaturated fatty acid was oleic(w₉) (45.205%) before soaking and (40.546%) after soaking. These results were in agreement with those of Girgis,( 2005) and Abdalla et al., (2007). The same table illustrated that the total essential fatty acid (omegas) achieved considerable levels ranged from (2.004-8.890%) of total fat.

Table(5):  Fatty acids content in mango seed kernels before soaking and after soaking (g/100gm)                 

The amino acids content of mango seed kernel are demonstrated in table(6).Data in this table showed that valine and leucine achieved higher values compared to  the FAO/WHO reference followed by therionine, lysine and phenylalanine which were somewhat equaled to the reference.         On the other hand, arginine and glutamic acids revealed the highest values of all non essential amino acids in MSK content. Meanwhile , both prolin and alanin were relatively closed and histidine, serine, glycine and ammonia contents gave the lowest values.

Table (6): The amino acids contained in mango seed kernel based on dry weight compared to the FAO/WHO reference.         .             

Table 7 illustrates the loss in moisture during baking and storage ,baking time and shelf- life at both room temperature and the refrigerator(5±1C) These data showed that blending mango seed kernel flour with wheat flour increased baking time and the loss in moisture during baking  up to the ratio 25%of MSK, but this loss in moisture decreased during storage at both room temp. and the refrigerator. The same table revealed that the shelf-life has increased in magnitude levels by increasing the incorporated ratio in treatments at both the room temp.( by 20 days ) and at the refrigerator ( by 39 days ). These results may be related to the many inhibitory phenolic compounds contained in this promising by product against microorganisms (Beuchat,1994) and the antioxidant agents, Soong et al.,( 2004) who suggested that mango seed kernels could be used as a potential source for functional  ingredients due to its high quality of fat and protein as well as high levels of natural antioxidants and antimicrobials. These results agreed with those of Ahmed et al.,(2007) who found that MSK contained 112 mg total polyphenols per 100g dry seed kernel powder .

Table (7): Effect of blending mango seed kernel flour with wheat flour on baking time , loss in moisture during baking and storage and shelf- life at room temp. and the refrigerator.

            Data in table 8 reveal the score of sensory evaluation of the produced pizza base loaf made by blending mango seed kernel flour at levels of 5,10,15, 20 and 25% (w/w) with wheat flour. The resultant data appeared that chewing, crust character, crumb color and grain and texture have improved at levels of 5and 10% treatments compared to the control, at the same time , there was graduate drop in the score of the appearance, crust character, the crumb color and grain & texture at the levels of 15and 20but they were acceptance in both flavor and chewing. On the other hand, the treatment 25% replacement had the lowest score for all parameters. The addition of mango seed kernel flour up to 15% did not affect on eating quality characters. This result was in agreement with the investigation of El-Soukkary et al.,(2000).

Table (8): Effect of blending mango seed kernel flour with wheat flour on the sensory evaluation of pizza base loaf.

Acknowledgment

The author wishes to express her gratitude to Al- Azhar university for the continues encouragement and facilitates the scientific research through  sharing the searchers in analytical payment.