Middle East Journal of Applied Volume : 07 | Issue :03 |July-Sept.| 2017 Sciences Pages: 613-625 ISSN 2077-4613

Functional characterization of luffa (Luffa cylindrica) seeds powder and their utilization to improve stabilized emulsions

Rabab H. Salem

Food Science and Technology Department, Faculty of Home Economics, Al- Azhar University, Tanta, Egypt. Received: 10 July 2017 / Accepted: 20 August 2017 / Publication date: 28 Sept. 2017

ABSTRACT

There is an increased necessity to discover new sources of proteins used as functional ingredients in different food systems. The aim of this research is using luffa (Luffa cylindrica) seeds for producing functional powder can be used as emulsifier agent with studying its nutritional properties. The results showed that, the content of crude protein obtained was 28.45%. The high total carbohydrate (60.95%) for Luffa seeds powder. The most concentrated amino acid in the seeds powder was glutamic acid (11.56 g/100g); while aspartic (10.98g/100g) was the most concentrated non-essential amino acids. On the other hand, the highest scoring essential amino acid was tyrosine (2.60); while threonine was the lowest scoring amino acid (0.97) making it the first limiting amino acid. The results also showed that, the bulk density was 0.40 g/cm3 for seeds powder. The water absorption capacity of luffa seeds powder was 235% while oil absorption capacity was 85% and the least gelation concentration was 12% which reveal its functional properties, thus it can be used for binding water and oil in food systems. The cytotoxic results showed that CC50 value of Luffa seeds powder on BHK cell line was >200 µg/ml. The emulsifying properties of O/W emulsion (ESS, ESC and TSE) were enhanced with the increasing level of luffa seeds powder but still lower than that of control (sodium casinate).

Key words: plant proteins, amino acids profile, phytochemical composition, emulsifying agent, cytotoxic activity.

Introduction

The problem of protein malnutrition in the developing countries is of great importance, as a large number of people in this part of the world do not have access to cheap protein sources (Adebowale and Lawal, 2003). Seeking sources of plant proteins has attracted increasing interest due to consumers’ growing concerns over the safety of animal-derived products. Recently, with rising public concern about increasing protein consumption and shortage, has stimulated research on developing new sources of protein from unexploited sources or wastes (Perumal et al., 2001). There is an increased necessity to discover new sources of proteins to be used as functional ingredients in different food systems. Plant proteins have been used extensively for many years in the food industry as food product ingredient due to amino acid content (Horax et al., 2004). Luffa (Luffa cylindrica) is a member of cucurbitaceouse family. One mature Luffa sponge will produce at least 30 seeds (Oboh and Aluyor, 2009). The seeds have laxative properties due to their high oil content. It contains a wide range of secondary metabolites with distinct biological activities. The seeds have been reported to be useful in the treatment of asthma, sinusitis and fever (Nagao et al., 1991). It is reported to possess antiviral, anti-tumor, antioxidant, anti-inflammatory and immunomodulatory activities (Tannin-Spitz et al., 2007). L .cylindrica seed contains a high proportion of essential amino acids and has a low atherogenic potential. Flavonoids (4.53%) were the most concentrated phytochemical in the seed flour while saponins, alkaloids and cardiac glycosides were also present (Lucy and Abidemi, 2012). Seeds are rich sources of minerals but the bioavailability of these minerals is usually low due to the presence of antinutrients (Valencia et al., 1999). These antinutrients interfere with absorption of nutrients from foodstuff thus affecting their metabolism. Soaking seeds/grains in alkali solutions (Reichert et al., 1980) have been reported to overcome the harmful effects in seeds. Treatment with sodium

Corresponding Author: Rabab H. Salem, Food Science and Technology Department, Faculty of Home Economics, Al- Azhar University, Tanta, Egypt. E-mail: [email protected] 613 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 bicarbonate solution is more economical and easier to handle than acid treatments (Mahmood et al., 2007). There are two basic forms of emulsion. The first is the oil-in-water (O/W) emulsion, in which oil droplets are dispersed and encapsulated within the water column, while the second is the water-in- oil (W/O) emulsion, in which droplets of water are dispersed and encapsulated within the oil (Gonglun and Tao, 2004). Protein and oil are two key ingredients in food emulsions (Melik and Fogler, 1998). Functional and physico-chemical properties of proteins such as texture, solubility, water absorption capacity, oil absorption capacity, foaming capacity, gel formation, etc. are indices that may be used in food formulations (Hermansson, 1979 ; Adeyeye and Aye1, 1998 and Soares de Castro et al., 2015) .The first objective of this study was to produce powder from Luffa seeds and characterize their nutritional and functional properties. The second objective was to develop model emulsion using Luffa seeds powder and characterize their emulsion properties.

Materials and Methods

Materials:

Luffa seeds:

Loofah gourds were harvested during the month of November. The gourds were shaken to remove the seeds manually. The seeds of (Luffa cylindrica) were collected from private farm at Abo- keeper City, El-Sharkia Governorate, Egypt.

Other Ingredients:

Corn oil was purchased from local market at Shubra-El-Kheima, Qaliubiya Governorate, Egypt. Sodium caseinate (90.34% protein, 5.83% water, 1.9 fat and 5.43% ash) and sodium benzoate were purchased from Chemicals Company El Rahma , Egypt .

Methods:

Preparation of luffa seeds powder:

The immature seeds and extraneous materials were removed. The remaining seeds were washed. They were soaked in 0.1% sodium bicarbonate for 12 hr. A seed to water ratio of 1:5 (w/v) was used. The soaked seeds were rinsed twice in distilled water and oven dried at 50 °C. The dried seeds were dehaulled manually. The sample was defatted by soaking in petroleum ether for 24 hours with shaking. The ratio of solvent to crushed seeds was 3:1(v/w). The soaking was repeated three times. luffa seeds powder packed in polyethylene bags and stored at 4°C until utilized.

Preparation of oil-in-water emulsions:

Oil-in-water emulsions (v/v) were prepared by the slow mixing of 10 ml corn oil (added gradually) with 90 ml of emulsifier solutions which prepared by dispersed of 1% (E1sample), 2% (E2sample), 3% w/v (E3sample) luffa seeds powder and sodium caseinate 1% w/v (control) into deionized water, followed by stirring for 2 h at ambient temperature, stored overnight at 4°C to ensure complete dissolution, then solutions were homogenized for 2 min at 3000 rpm .Sodium benzoate was added at a concentration of 0.1 w/v in the continuous phase as an antimicrobial agent.

Analytical Methods:

Proximate composition:

Moisture, ash, protein, fat and fiber content were determined according to AOAC (2005). Moisture was determined by drying sample at 105°C to constant weight. Ashing was performed at 550 °C for 6 hrs in a muffle furnace. Protein was analyzed using kjeldahl method; factor of 6.25 was

614 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 used for conversion of nitrogen to crude protein. Fat was calculated by weight loss after extraction with petroleum ether in sohxlet apparatus. Crude fiber was determined. Carbohydrate contents were estimated by differences. The energy values obtained for carbohydrates (x17kJ), crude protein (x17 kJ) and crude fat (x37 kJ) for the sample.

Minerals analysis:

Minerals were determined by the method described by AOAC (2005) at the High Institute of Public Health, Alexandria. Sodium, potassium and calcium were determined using Flame photometer apparatus. Magnesium, iron, zinc and manganese were determined using Atomic Absorption Spectrophotometer.

Amino Acids Analysis:

The amino acids profile was determined using methods described by (Cohen et al., 1985) using Amino Acid Analyzer (Beckman, model No119 CL) at the Faculty of Agriculture, Mansoura University, Egypt. The sample was hydrolyzed with 6N hydrochloric acid (10 ml) with 0.1% mercaptoethanol in a sealed tube at 110 °C for 24 hours. After cooling at room temperature, the hydrolyzed samples were filtered through Whatman No. 1 filter paper and the filtrate was diluted with distilled water to 25 ml in a volumetric flask. 5 ml of the diluted filtrate was dried in a vacuum desiccator in the presence of potassium hydroxide. The result dried residue was dissolved in 1 ml of sodium citrate buffer (pH 2.2) and stored at 4°C until analysis.

Functional properties:

Bulk density:

Bulk density determination carried out using the procedure of Mepba et al. (2007). A specified quantity of the sample was transferred into a weighed measuring cylinder (W1). The cylinder containing the sample was weighed (W2). The bulk density was determined from the relation:

Bulk density (%) = W2 −W1 /Volume of sample

Water absorption properties:

Water absorption capacity was determined using the method of Sathe and Salunkhe, (1981) as modified by Adebowale et al. (2005). Ten milliliter of deionized water was added to 1.0 g of the sample in a beaker. Followed by centrifuging at 3500 rpm for 30 min and the supernatant measured in a 10 mL graduated cylinder. The water absorption capacity has been expressed as a percentage:

Weight of absorbed water x100 Water absorption capacity (%) = Sample weight

Oil absorption properties:

The oil absorption capacity of sample was determined by the method of Ghavidel and Prakash (2007). A sample was mixed with 5 mL of corn oil in a centrifuge tube for 1 min, held for 30 min at room temperature, and centrifuged for 25 min at 5000 rpm. The oil layer on the top of the sample was decanted and the tube was inverted for 5 min to drain residual oil, and then reweighed. The oil absorption capacity has been expressed as a percentage: Weight of absorbed oil Oil absorption capacity (%) = x100 Sample weight

615 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613

Emulsion properties:

The emulsion capacity was determined following the procedure of Yasumatsu et al. (1972).20 mL of distilled water was used to make slurry of 1g of the sample at 100 rpm for 15 min. 5 mL of corn oil was added and stirred at 1000 rpm for 1 min. It was centrifuged at 2000 rpm for 5 min. The ratio of the height of the emulsion layer to the height of the liquid layer was calculated as the emulsion capacity expressed in percentage. The emulsion stability was estimated after heating the emulsion in a centrifuge tube at 80 0C for 30 min in a water bath, cooling for 15 min under running tap water and centrifuging at 2000 rpm for 15 min. The emulsion stability, expressed as a percentage was calculated as the ratio of the height of the emulsified layer to the height of the liquid layer.

Foaming properties:

The foaming capacity and stability were studied by the method of Coffman and Garcia (1977). A known weight of the sample was dispersed in 100 mL distilled water with recording the volume. The resulting solution was homogenized for 5 min at high speed and the volume of homogenized solution was recorded to calculate the foam capacity by using the following equation:

Vol. after homogenization - Vol. before homogenization Foaming capacity (%) = x100 Vol. before homogenization

While the foam stability was calculated by dividing the volume of the homogenized solution after keeping for 24 h by its volume after homogenization by using the following equation:

Vol. after homogenization Foaming stability (%) = x100 Vol. after 24 h

Least gelation concentration:

Gelation property was investigated using the method described by Coffman and Garcia (1977). Sample suspensions of 2-20% were prepared in distilled water. Ten milliliter of each of the prepared dispersions was transferred into a test tube. It was heated in a boiling water bath for 1 h, followed by cooling. The test tubes were further cooled at 4°C for 2 h. The least gelation concentration was determined as the concentration when the sample from the inverted test tube did not slip or fall.

Phytochemical composition:

Total alkaloids content:

Total alkaloids content were determined according to (Fzel et al., 2008). Sample was dissolved in 2N HCL and then filtered. The extracts were collected in a 10 mL graduated cylinder and diluted to volume with chloroform. The absorbance of the complex in chloroform was measured at 470 nm.

Total glycosides:

Total glycosides of sample was quantitatively determined according to Solich et al. (1992). Sample was mixed with 10 mL freshly prepared Baljet's reagent (95 mL of 1% picric acid + 5 mL of 10% NaOH). After 1 hr, the mixture was diluted with 20 mL distilled water and the absorbance was measured at 495 nm by spectrophotometer. Total glycosides were expressed as percentage.

Tannins:

Sample was weighted; 50 ml of distilled water was added and shaken for 1 h. This was filtered into a 50 ml volumetric flask. 5 ml of the filtrate was pipette out into a tube and mixed with 3ml of

616 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613

0.1M FeCl3 in 0.1N HCl and 0.008 M potassium ferrocynide. The absorbance was measured with spectrophotometer, within 10 min. A standard was prepared using tannic acid to get 100 ppm and measured the absorbance (Van-Burden and Robinson, 1981).

Saponin:

Sample was weighted and dispersed in 100ml of 20% ethanol. The suspension was heated for 4 h at 55 °C. The mixture was filtrated and the residue was re-extracted with another 200 ml of 20% ethanol (Obadoni and Ochuko 2001). The concentrated extracts were transferred into a 250 ml separating funnel and 20 ml of diethyl ether was added. 30 ml of n-Butanol was added. The saponin content was calculated in percentage.

Total flavonoid content:

The total flavonoid content was determined according to Zulueta et al. (2007), using aluminum chloride (AlCl3) colorimetric assay. 300 µL of 5% sodium nitrite (NaNO2) was mixed with 100 µL of extract. 300 µL of a 10% AlCl3 solution was added. The mixture was centrifuged at 5000 rpm for 10 min. Absorbance of the supernatant was measured at 510 nm wave length.

Cytotoxicity assay:

Cell toxicity was monitored on Vero cells at the Regional Center for Mycology and Biotechnology (RCMB) at Al-Azhar University. BHK cells were treated with Luffa seeds powder at various concentrations (0 – 200 µg) for 48 h. After that, cytotoxicity of extract was determined by a cell cytotoxicity concentration 50% growth cytotoxic concentration 50 (CC50) In Brief, Vero cells were propagated in Dulbecco’s modified Eagle’s medium. The cells were maintained at 37 ºC in a humidified atmosphere with 5% CO2 for 24 hrs. The cytotoxicity assay was carried out using 0.1ml of cell suspension, containing 10,000 cells seeded in each well of a 96-well microtitre plate (Falcon, NJ, USA). Fresh maintenance medium containing different dilutions of the tested sample was added after 24 hrs of seeding. The plates were incubated at 37 ºC in a humidified incubator with 5% CO2 for a period of 48 hrs. Six wells were used for each concentration of the tested compound. The cytotoxicity effect was scored (Vijayan et al., 2004).

Characterization of emulsions:

Stability of emulsions during storage:

The emulsions were placed into test tubes, and stored at 20 oC for seven days (Demetriades et al., 1997). The stability of the emulsions during storage (ESS) was estimated as: Final emulsion height ESS (%) = x100 Initial emulsion height

Emulsions stability at centrifugation:

The emulsions were placed in: centrifuge tubes, and centrifuged for 10 min at 3000 rpm. The emulsions stability at centrifugation (ESC) was estimated as:

Emulsion height after centrifugation ESC (%) = x100 Initial emulsion height

Thermal stability of emulsions:

The emulsions were placed in test tubes and were heated at 1 oC/min to achieve 80 oC for 10 min. The samples were cooled and stored overnight at 4 oC. The water-phase on top of the test tubes

617 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 was removed carefully (Ionescu et al., 2008). The thermal stability of the emulsions was reported as a creaming index

Wi - Wt TSE (%) = x100 Wi Where Wi and Wt are the weights of emulsion before and after thermal treatment, respectively.

Statistical analysis:

The statistical analysis was carried out using SPSS. Statistical software (version 11.0 SPSS Inc., Chicago, USA) as reported by Snedecor and Cochran, (1980).

Results and Discussion

Proximate composition of luffa seeds powder:

The proximate composition of luffa seeds powder is presented in Table 1. The moisture content for powder was very low 4.93 % which is within the acceptable range for a good keeping period. Moisture content is a major quality factor in the preservation of some food products and it affects food stability (Nielsen, 2010).The relatively low moisture content is an indication that this flour will has high shelf life especially when properly packaged against external conditions. The crude protein content obtained for powder was 28.45%. This suggests that, luffa seeds powder may be useful as a protein supplement in the diet of malnourished people. Proteins are essential component of the diet needed for survival of animals and humans, which function basically in nutrition by supplying adequate amounts of required amino acids (Pugalenthi et al., 2004). The crude fiber content obtained was 1.67%, they are reputed to have several beneficial health effects including delaying the release of carbohydrates, lowering of blood lipids, and prevention of colon cancer (Tosh and Yada, 2010). The total ash content obtained for the powder 2.98%. Ash content is important in food for quite number of reasons (Pomeranz and Clifton, 1981). The high total carbohydrate (60.95%) of the luffa seeds powder suggests that, the powder is a good source as an additive to other materials for forming gel in food products. The energy content obtained for powder was 1557.54 kJ/100g. Dairo et al., (2007) reported that, the proximate composition of luffa seed was as follows, crude lipid 25.64%, crude protein 25.59%, crude fiber 6.50%, ash 7.32% and finally, carbohydrate 30.62% (on dry basis). Rao and Rao (1986) have reported 20-71% and 60% losses in dry matter of salseed meal as a result of washing after soaking in sodium hydroxide and sodium carbonate, respectively.

Table 1: Proximate composition (% on dry basis) of luffa seeds powder Component Value Dry matter 95.07 Crude protein 28.45 Ether extract 1.02 Total ash 2.98 Crude fiber 1.67 * Total carbohydrate 60.95 Food energy(KJ/100g) 1557.54 Values are given as means of three replicates. Total carbohydrate was estimated by difference.

Minerals composition of luffa seeds powder:

The minerals content of the luffa seeds powder in mg/100 g was depicted in Table 2. Iron and zinc are among the essential elements for humans and their daily requirements for adult are 15 and 18 mg, respectively (Kampali and Pali, 2004). Though the level of iron and zinc are low in the seeds, they could contribute partially to the overall daily intake of these elements. The most abundant mineral in the studied powder was magnesium with value 5.20 mg/100g. Magnesium has been

618 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 reported to be an important co-factor of many regulatory enzymes, particularly the kinases (WHO, 2002). The potassium value 2.14 mg/100 g powder, this is beneficial in the management of diabetes since potassium helps to control blood pressure and possibly prevents stroke (Ibeanu et al., 2012). The calcium content 0.35 mg/100 g; it has been help in bone formation and blood coagulation. The zinc value of the luffa seeds powder was 0.13mg/100 g. Sodium is an important source of electrolytes within the body, in the studied sample was 2.15 mg/100 g. Manganese was present in appreciable amount. Generally from the recommendation by NRC/NAS, the daily requirement of Zn, Mn and Cu can easily be met while the diets may need be supplemented with foods high in K, Na, Ca and P. Content rations of Mg, Ca, Na and Mn were 6.44, 0.65, 3.81 and 0.12 % in luffa seeds ( Dairo et al., 2007).

Table 2: Minerals content (mg / 100g on dry basis) of luffa seeds powder Element Value Potassium 2.14 Magnesium 5.20 Calcium 0. 35 Sodium 2.15 Iron 0.27 Zinc 0.13 Manganese 0.08

Amino acids composition of luffa seeds powder:

The nutritive value of a protein depends primarily on the capacity to satisfy the needs from nitrogen and essential amino acids (Pellet and Young, 1980). Table 3 shows the amino acid profile of L. cylindrica seeds powder. The most concentrated amino acid in the seeds powder was glutamic acid (11.56 g/100g), while aspartic (10.98 g/100 g) was the most concentrated non-essential amino acids. The methionine content in the sample (2.90 g/100 g) was found to be higher than that of soyabean 0.9g/100g (Akintayo et al., 2002).While the lysine content (4.56g/100g) was higher than that reported by Aremu et al. (2008) for L. cylindrica seed kernel (2.9g/100g). The concentrations of isoleucine (3.62g/100g) and valine (4.82g/100g) were found to meet the FAO/WHO (1991) requirement for these two essential amino acids (2.8g/100g and 2.5g/100g respectively) for school children. The total essential amino acids with Histidine for L. cylindrica (30.89g/100g) was found to meet the FAO/WHO (1991) requirements (23.20g/100g) for essential amino acids with histidine. The amino acids scores of L. cylindrica seeds powder were also shown on Table 3. The highest scoring essential amino acid was tyrosine (2.60) while threonine was the lowest scoring amino acid (0.97) making it the first limiting amino acid. leucine (1.02) making it the second limiting amino acid.

Functional properties of luffa seeds powder:

Functional properties play a major role in the physical behavior food ingredients during their preparation, processing and storage (Fennema, 1996). Determining the functional properties of proteins aids in selecting plant food raw material with the required properties in specific food formulations (Jyothi and Kaul, 2011). The bulk density (weight of sample per unit volume) was 0.40 g/cm3 for L. cylindrica seeds powder. The low bulk density of the powder would be potentially advantageous in the preparation of food formulations. The foaming stability of the powder was 48 %, this means the powder will exhibit better potential as a foaming and stabilizing agent. Data presented in Table 4 show that L. cylindrica seeds powder had high water absorption capacity (235 %).The results of these investigations suggested that seeds may be useful in food formulations such as bakery products where, hydration to improve handling characteristics is required. The oil absorption capacity of powder was high (85 %) indicating a good ability to effective additive in products such as meat formulations. The rate of L. cylindrica seeds powder emulsion stability (ES) was 50 %. The high emulsion stability suggests the possible use of powder in stabilizing colloidal food systems. Least gelation concentration 12% recorded by L. cylindrica seeds powder. This value compared favourably with those reported for different chickpea cultivars (12-16%) by Kaur and Singh (2005). Moure et al. (2006) had associated the variation in gelling properties to the ratio of different constituents such as

619 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 protein, lipids and carbohydrates in different legumes. Gelation takes place more readily at higher protein concentration because of greater intermolecular contact during heating. Results of this study suggest that, powder of L. cylindrica seeds can be potentially used as functional ingredients, nutrition supplements, and emulsifiers.

Table 3: Amino acid composition (g/100g protein) of luffa seeds powder compared with FAO/WHO reference protein Aminoacids (A.A) Value FAO/WHO Amino acid scores (%) Leucine2nd 4.49 4.4 1.02 Isoleucine 3.62 2.8 1.30 Methionine 2.90 2.2 1.32 Phenylalanine 4.77 Tyrosine 0.94 2.2* 2.60 Lysine 4.56 4.4 1.04 Threonine1st 2.73 2.8 0.97 Valine 4.82 2.5 1.93 Histidine 2.06 1.9 1.10 Total essential AA 30.89 23.20 Arginine 8.45 Aspartic 10.98 Glutamic 11.56 Serine 3.43 Proline 2.45 Glycine 0.72 Alanine 3.15 Cystine 0.36 Total non essential A.A 41.10 Total A.A 71.99 * Phenylalanine +Tyrosine , 1first limiting amino acid ,2 second limiting amino acid Scores were calculated using the following formula (FAO/WHO, 1991)

Table 4: Functional properties (%) of luffa seeds powder Property Value Bulk density (g/cm3) 0.40 Foaming capacity 39 Foaming stability 48 Water absorption capacity 235 Oil absorption capacity 85 Emulsion capacity 40 Emulsion stability 50 Least gelation concentration 12 Values are given as means of three replicates.

Phytochemical compounds of luffa seeds powder:

The phytochemical compounds of the Luffa seeds powder are listed in Table 5. These are compounds that limit the wide use of many plants as natural compounds (Kubmarawa et al., 2008). These anti nutritional factors tend to bind to elements by forming indigestible complex .They are below the established toxic level (Nkafamiya and Manji, 2006). Saponin is known for this bitter taste, foaming in aqueous solutions, and this ability to haemolyse red blood cells (Birk and Peri, 1980). Saponin has been found to possess hypocholesterolemic property (Oakenfull and Sidhu, 1990), which is important for the control of high blood lipids. The presence of saponin may account for the reported therapeutic actions of L. aegyptiaca seeds (Elemo et al., 2011). The concentration of saponin in the Luffa seeds powder was 0.15 g/100g, this value was respectively lower reported for medicinal plant (Edeoga et al., 2005). The concentration of alkaloid in the L. cylindrica seeds powder was 0.22 g/100g. Value of flavonoids (1.30mgCE/g) was the highest concentrated phytochemical in the seeds powder. Flavonoids possess better antioxidant abilities than those of vitamin C and E (Bagchi et al., 1999). Flavonoids protect against platelet aggregation, hepatotoxins, and viruses (Okwu and

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Omodamiro, 2005). The glycosides level in the Luffa seeds flour was found to be 0.10 mg/100 g. Tannins induce a negative response when consumed; these effects can have a delayed response related to antinutritional/toxic effects (Ogunleye and Ibitoye, 2003). Level of tannins in the flour was 0. 54 mg/100g, which well below the level that is considered unacceptable (1%) for condensed tannins (Price et al., 1978). Chemical treatment (NaHCO3) for detoxification of Luffa seeds powder was most effective. Salunkhe et al. (1990) concluded that alkali solutions were generally more efficient in deactivating antinutritional compounds than acidic or ash treatments.

Table 5: Phytochemical compounds (g/100 g) of luffa seeds powder Property Value Saponin 0.15 Alkaloid 0.22 Glycosides 0.10 Tannin 0 .54 Flavonoid (mgCE/g) 1.30

Cytotoxic activity of luffa seeds powder:

Baby Hamster Kidney (BHK) has used to assess the effects of extracts on the proliferation of normal cells. The results of cytotoxic activity of the powder are presented in Table 6. The cytotoxicity of the cells was directly proportional to the concentration of the powder. These results showed that, there were decreasing in viability of the treated cells by increasing of the powder concentration. At concentration of 25 µg powder; the viability of cells was about 96.20 %. When the concentration was decreased (3.125 µg), the viability of cells was 100 %. The CC50 value of Luffa seeds powder on BHK cell line was >200 µg/ml. This study shows that luffa seed has a low atherogenic potential.

Table 6: Cytotoxic activity of luffa seeds powder Sample conc.( µg) Viability % 0 100 3.125 100 6.25 100 12.5 98.89 25 96.20 50 95.54 100 92.32 200 90.48 CC50 >200

Emulsions characterization:

The emulsifying properties of O/W emulsions were determined by evaluating the emulsion stability during storage (ESS), emulsion stability at centrifugation (ESC) and thermal stability of emulsions (TSE) are presented in Table 7. O/W emulsions added by seeds powder showed improvement value of ESS 65.78 % for control emulsion decreased to 47.56%, 53.12 and 59.45 with E1, E2 and E3 emulsions respectively. Emulsion stability was dependent on emulsifier concentration and disperse phase volume. Model emulsions presented an ESC of 42.68% for control emulsion. An ESC of 28.00% was obtained for E1emulsion increased to 33.43 % with E2 emulsion and 37.43% with E3 emulsion. The results of thermal stability for emulsions indicate that, the highest stability 69.18 % was obtained for the control emulsion (1%NaCas). It has been proposed that a degree of denaturation might promote an improvement in the emulsifying properties by exposing the hidden hydrophobic groups of the globular proteins (Harper, 1992 and Voutsinas et al., 1983). An appropriate degree of denaturation is related to a suitable balance of the hydrophilic and hydrophobic groups of the protein molecule after denaturation (Aoki et al., 1981). Stability of emulsions can be formed by adding emulsifiers and/or thickening agents to overcome the activation energy of the system. In our study, addition of Luffa seeds powder solution led to more emulsion stability as emulsifier materials. Finally

621 Middle East J. Appl. Sci., 7(3): 613-625, 2017 ISSN 2077-4613 the emulsifying properties of O/W emulsion (ESS, ESC and TSE) were enhanced with the increasing level of luffa seeds powder but still lower than that of control (sodium casinate).

Table 7: Characterization of O/W emulsions Emulsions Parameter Control E1 E 2 E3 ESS 65.78a 47.56b 53.12ab 59.45a ESC 42.68a 28.00b 33.43ab 37.43a TSE 69.18a 48.82c 55.46b 61.70b In a row, means having the same superscript small letters are not significantly different at 5% level for emulsions (ESS) Emulsion stability during storage. (ESC) Emulsion stability at centrifugation. (TSE) Thermal stability of emulsions.

Conclusion:

From the previous results, it could be concluded that, Luffa seeds are a good source of protein, carbohydrate, crude fiber. Luffa seeds powder has a good potential for incorporation into O/W emulsions to act as emulsifier agent (functional ingredient).

References

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