, Description:DETAILED DESCRIPTION OF THE INVENTION
FIELD OF INVENTION
This invention refers to a process of defatted, debittered and off-flavor free guar flour with high protein content, thereby improving its commercial value, utility, and use range of guar meal, the guar industry by-product that is otherwise a low value product mainly used as poultry and cattle feed and that too in limited doses as such or as part of feed formulation ingredient.
BACKGROUND OF THE INVENTION
Guar (Cyamopsis tetragonobola) is an important drought resistant annual legume used primarily as fodder crop. It is a major supplementary protein source to the cattle composed of 30-33% hull, 27-30% endosperm and 43-47% germ (Lee et al 2004). This is kharif crop which is sown alone or in a mixture with non-legumes like jowar or bajra. Average protein content in guar seed is about 10-15% which makes it a productive fodder. India is the major producer of guar seed contributing 80% of guar seed for the world market followed by Pakistan (15%). The largest guar producing state in India is Rajasthan (70%). Other states like Haryana, Gujarat and Punjab also contributed to guar seed production, their share in India’s production being 12, 11 and 3%, respectively. Guar gum has significant application in industry as it is also a source of natural hydrocolloid and is soluble in cold water which forms thick solutions at low concentrations. This property makes it useful in mining, petroleum drilling and textile manufacturing (Wong and Parmer 1997). The world market from guar gum is estimated to be around 0.15 million metric lakh tonnes per year, out of which 85% is produced by India and Pakistan. The main demand of guar seed originates from the US petroleum industry and the oil fields of Middle East. Guar gum, the commercial product has ample applications in food industry as well. It is used as gelling, viscosifying, thickening, clouding and binding agent as well as for stabilization, emulsification, preservation, water retention and enhancement of water soluble fibre content.
The by-product of guar gum industry called guar meal consists of seed coat and germ material. Guar meal comes in two forms: Guar meal churi and Guar meal korma.The guar meal is a potential source of protein as it contains 35 to 47.5% crude protein, which is one and a half times more than the level of protein in the whole guar seed. The guar meal at lesser concentrations is used as feed for livestock including poultry. Guar meal has a few deleterious substances as anti-nutritional factors such as residual gum, polyphenols, lignin, trypsin inhibitors, saponins and some organic acids, aldehydes and cyanogens with foul smell and bitter taste (Srivastava et al 2011). Due to presence of these undesirable substances, guar meal has limited use in livestock feed and almost negligible use in foods for human consumption. Several researchers believe that trypsin inhibitor is the primary antinutritional factor that limits the use of guar meal (Couch et al 1967 and Lee et al 2003) but a recent report by Nidhina and Muthukumar (2015) has revealed only negligible amount of tripsin inhibitor as compared to soybean meal. Guar seed may contain more trypsin inhibitor and it might have been deactivated during the gum extraction procedure, where it undergoes heat treatment upto 100ºC. Saponins are widely distributed in the plant kingdom (Sparg et al 2004). They are found to impair the digestion of protein and absorption of minerals and vitamins in the gut, at the same time, they are found to have antioxidant properties (Francis et al 2002). The saponin content of the different fractions of industrial guar meal falls in the range of 27.5 to 29.2 mg per g on a dry matter basis as reported by Nidhina and Muthukumar (2015). Previous reports indicated that the saponin content of guar meal ranged from 50 to 130 mg/g on a dry matter basis (Shahbazi et al 2012). This explains that considerable reduction of saponins occurred during the processing of guar meal to industrial guar meal compared to that of laboratory processed guar meal. The industrial process includes heat treatment which is responsible for reduction of saponin content in industrial guar meal.
Lower quality and quantity of protein in traditional Indian diets result in widespread protein malnutrition among children and adults. Though the high nutritive value of guar meal has been well recognized, the pungent and prohibitive beany off flavour and bitter taste that are attributed to some phospholipids or fat soluble compounds contained in it, makes it unfit for human consumption. A process needs to be standardized for the preparation of an off-flavour free Guar Meal Flour so that it can be enriched in commonly consumed food products to enhance the protein content of the final product and make them commercially accepted health foods. Further, guar proteins can be extracted by using suitable solvents followed by acid precipitation to prepare guar protein isolate which can be also be supplemented in extruded snacks and bakery products after optimum standardization.

STATEMENT OF INVENTION
This invention involves a novel process of removing unpleasant flavour and prohibited taste causing factors from guar meal using solvents such as ethyl alcohol, hexane, gamma valerolactone (GVL) and limonene thereby the resultant nearly defatted, debittered and off-flavour free flour rich in protein content can be a potential protein supplement of plant origin with higher economic value, as compared to animal proteins, that can be used to enrich various food preparations to get human edible high protein products
DETAILED DISCLOSURE OF THE INVENTION
Guar meal is treated with solvents that are generally recognized as safe (GRAS) and are used in food processing such as i.e. ethanol, hexane, gamma valerolactone (GVL) and limonene. In detail, the extraction process comprises following steps for a complete process for preparation of nearly defatted, debittered and off-flavor free protein rich Guar Meal Flour. The process involves recruitment of discrete methodological sets independently and/or in any combination and/or integration. The essence of methodological sets are explained below:-
1.7. The guar meal is ground to a fine powder in an electric grinder or otherwise to have particle size preferably ranging between 70 to 100 mesh.
1.8. A guar meal powder is then extracted with undiluted (95%) ethanol preferably in a ratio of 1:2 to 1:5. The extraction time ranges preferably between 30 minutes to two hours. The ethanol is drained or decanted or otherwise removed from the mixture thus, also removing the ethanol soluble materials. The residual ethanol is removed from the powdered meal preferably by vacuum evaporation applying heat at about 40-60º C with a condenser in the line.
1.9. The guar meal powder with or without residual ethanol is extracted with n-hexane for three hours. The meal and solvent ratio is preferably 1:5 to 1:10 v/v. The extraction step is repeated till most of the fat of the guar meal powder is removed so that the residual fat in the meal is preferably less than 0.2%. The hexane from each cycle is recovered for recycled use.
1.10. To remove the residual hexane, the meal is preferably centrifuged and supernatant hexane is removed, the sediment is preferably dried by applying mild heat treatment (40 to 60º C) to remove the residual hexane. The material thus obtained is a defatted nearly bland Guar Meal Flour (GMF) which can be used as protein supplement for enriching various food preparation process and products.
1.11. The two fat fractions that are solubilized in ethanol (1.70%) and hexane (3.73%) are also collected. The fat soluble fractions have pungent and off-flavour, hence maybe suitable for use in non-food industry.
1.12. Also the guar meal sample is extracted with GVL or limonene preferably in the ratio of 1:2 to 1:4 (v/v) preferably for 4 to 8 hours. To remove the residual solvent, the meal is centrifuged and supernatant is removed, the sediment is dried by applying mild heat treatment (40 to 60º C) to remove the residual solvent.

Example 1: Preparation of defatted, debittered and off-flavor free Guar Meal Flour (GMF) with high nutritive value
Powdered guar meal korma 100 g is extracted with 500 ml of undiluted ethanol (95%) for one hour. The ethanol is drained from the mixture thus, removing the ethanol soluble materials from the korma. The residual ethanol from defatted korma is removed by vacuum evaporation. The guar meal powder is then extracted with 500 ml of n-hexane for three hours. The extraction step is repeated twice so that the fat from the guar meal powder is removed and the resultant fat in the meal is preferably less than 0.2%. The hexane in each cycle is recovered for reuse. The fat recovered from ethanol and hexane extraction is 1.7 and 3.73% of biomass, respectively.
The proximate composition of defatted GMF is estimated and results are given in Table 1. The GMF has protein content of 41.51 % which implies lower than the korma. The ethanol and hexane extraction process results in a loss of 18.3% of the total proteins. Though there is a nutritional loss during this extraction process, it may be compensated by loss of bitter and off-flavour compounds as well. The reduction in protein may be due to solubility of some protein fractions in alcohol/organic solvent during extraction process. GMF has negligible amounts of fat as compared to korma. The moisture, crude fibre and ash contents were statistically similar in korma and GMF. GMF is rich in proteins and has lesser fat and carbohydrates, hence suitable for enrichment of cereal flours for enhanced protein and lesser calorific value.

Table 1 Nutritional composition of Guar meal korma and Guar Meal Flour (GMF)
Parameter Guar meal korma Guar Meal Flour
Moisture, g/100g 7.26 ± 0.05 8.02 ±0.08
Protein, g/100g 50.81 ± 0.98 41.51 ± 0.76
Fat, g/100g 5.27 ± 0.24 0.20 ± 0.08
Crude fibre, g/100g 6.92 ± 0.87 6.95 ± 1.13
Ash, g/100g 5.52 ±0.57 5.50 ± 0.46
Available carbohydrates, g/100g 24.22± 1.87 37.82± 1.90
Saponins, g % 0.58 ± 0.08 0.67 ± 0.09
Trypsin inhibitor activity, TIU mg/g protein 39.46 ± 1.30 36.9 ± 1.07

Values Mean ± SD of three replications

The saponins in korma and GMF are 0.58% and 0.67 %, respectively. Saponins in GMF is comparable to their concentration in various commercial soybean flours (0.43-0.67%) but lesser than soy protein isolate (0.76%) as reported by Philips et al (1986).
Trypsin inhibitor activity of korma and GMF is 39.46 and 36.90 TIU mg per g protein. Trypsin inhibitor activity is lesser in GMF as compared to that known for soybean flour (43-84 TIU/ mg protein (Guillamon et al 2007). The GMF has closer values for saponins and trypsin inhibitors in comparison to soybean meal. Moreover, the GMF would be used in the product development where heat treatment is necessary, this may result in further reduction in these two anti-nutrients in the final products.
Amino acid composition of Guar meal korma and GMF is shown in Table 2. Both the products are close to each other in their amino acid makeup. Sulphur amino acids are low but other amino acids are present in substantial amounts in GMF. Guar meal proteins has the amino acid makeup comparable to soy meal proteins (Banaszkiewicz (2011). Similar to defatted soybean flour, the GMF can be supplemented in cereal flours to mutually balance their limiting amino acids.
Table 2 Amino acid profile of Guar meal korma and Guar Meal Flour (GMF) protein
Amino acid Amino acid content (%) in protein fraction from
Guar meal korma Amino acid content (%) in protein fraction from
Guar Meal Flour
Histidine 3.34 3.13
Serine 4.11 3.75
Arginine 10.19 9.67
Glycine 8.11 7.03
Aspartic acid 15.14 14.51
Glutamic acid 17.5 20.44
Threonine 3.26 2.29
Alanine 4.04 4.42
Proline 5.03 6.55
Cysteine 0.57 0.29
Lysine 4.28 4.22
Tyrosine 5.13 4.51
Methionine 1.68 1.15
Valine 2.42 2.7
Isoleucine 2.2 2.57
Leucine 6.84 7.05
Phenylalanine 6.16 5.72

The mineral content of guar meal korma and Guar Meal Flour has been shown in Table 3. The results showed that the mineral content of both the products is almost similar indicating that there is no loss of minerals during the standardized extraction process. Though all the minerals are present in good amounts, but iron (41.33 mg/100g) and zinc (6.40 mg/100g) are present in appreciable amounts. Therefore, GMF can be used to supplement the common food products in order to enhance iron and zinc content to help address the problem of micro-nutrient deficiency to some extent
The water absorbing capacity (WAC) and swelling capacity (SC) of Guar Meal Flour is 3.47g of water per g and 19.7% and is higher than other legume flours such as green gram flour (Chandra and Samsher 2013), soybean flour (Ali et al 2012) and lupin flour (Salem and Ahmed 2012). The higher WAC and SC is a critical function of its protein, thereby makes it suitable for viscous foods like soups, gravies, doughs and baked products. The oil holding capacity (OHC) is also higher (2.62g of oil per g) than cereal flours but comparable with other legume flours (Ali et al 2012 and Chandra and Samsher (2013). The ability of guar proteins to bind with oil makes it useful in food systems where optimum oil absorption is desired. This may give some advantage for bakery products such as cakes or biscuits and may improve mouthfeel and flavour retention which require a good oil absorbing capacity.

Table 3 Mineral content of Guar meal korma and Guar Meal Flour (GMF)

Mineral, mg/100g Guar meal korma Guar Meal Flour
Iron 40.89±1.94 41.33±2.55
Copper 1.71±0.07 1.86±0.10
Zinc 6.40± 0.33 6.44±0.36
Calcium 31.24±0.84 34.55±0.51
Magnesium 350.56±12.49 344.78±6.59
Sodium 43.42±6.58 43.61±10.14
Potassium 1414.24±44.53 1476.63±35.20
Chromium 0.05±0.01 0.02±.06
Manganese 2.12±0.05 2.19±0.04
Cobalt 0.02±0.01 0.03±0.01

Values are Mean ±SD

Table 4 Functional properties of Guar Meal Flour (GMF)
Properties Guar Meal Flour
Water Absorption Capacity, g of water/g 3.47± 0.12
Oil Holding Capacity, g of oil/g 2.62 ± 0.06
Swelling capacity 19.7± 1.26
Emulsifying activity, % 56.33 ± 3.03
Emulsifying capacity, % 73.08 ± 5.48
Foaming activity, % 155.4 ± 1.4
Foaming stability, % 91.4 ± 1.0

The emulsifying activity (EA) and emulsifying stability (ES) of Guar Meal Flour is 56.33 and 73.08% while foaming capacity and activity is 145.4 and 91.4%, respectively. The values for emulsifying and foaming properties are higher in comparison to other legume flours due to its higher protein content (Chandra and Samsher 2013; Ali et al 2012 and Salem and Ahmed 2012). The capacity of guar protein to enhance the formation and stabilization of emulsions is important for its applications in food products.

Claims:We claim:

1. A process of preparing defatted, debittered and off-flavor free guar meal or flour to improve its commercial value, utility, and use range including for human food and nutrition wherein the process involves independent or sequential steps of extraction with food suitable organic solvents like ethanol, hexane and gamma valerolactone and limonene singly or in combination with inbuilt steps of solvent recycle and
2. As claimed in claim 1, the defatted and off flavor free guar meal flour (GMF) is suitable for use as such or as food process or product ingredient.
3. As claimed in claims 1 and 2, the edible GMF has nutritional attributes of being rich in proteins and certain micro-nutrients like iron, zinc and copper for use in development of nutritional products and addressing problems of malnutrition.
4. As claimed in claims 1 to 3, the nutritional and functional properties of GMF make it suitable for use in extruded and bakery products.
5. As claimed in claims 1 to 4, the GMF is beneficial for use as a source of protein and technical ingredient for production of whipped food products due to its excellent foaming propertiesand also for the development of extruded products.
6. As claimed in claims 1to 5 , the process is applicable to guar whole seed, seed meal, guar meal korma, guar meal churi and other products or by-products from guar seed processing.