Procurement and preparation of plant materials
In this experiment, 11 different flowers, namely (
Celosia cristata var
. Deep Armor Purple
, Celosia cristata var. Twisted Orange
, Celosia cristata var. Pink
, Celosia argentea var
. Cristata Yellow
, Celosia argentea var
. Plumosa
, Celosia cristata var
. Bombay Pink
, Gomphrena globosa, Gallardia pulchella, Tagetes erecta, Tagetes patula, Calendula officinalis) were used as an experimenal material. The flower crops were sown, transplanted and maintained in agri farm, Department of Horticulture, School of agriculture, LPU, Punjab. Those flowers were dried at room temperature for 5 hours, followed by tray dryer for 8 hours at 55°C.
Proximate constituent analysis
Moisture content
Hot air oven was used to dry petridish at 105°C for 1 h in order to remove the moisture and weighed (W1). The sample (5 g) was then added to petridish and oven dried at 135°C for 2 h and final weight (W2) was taken.
Ws = Weight of sample.
W1 = Weight of petridish.
W2 = Weight of petridish after drying.
Ash content
A porcelain crucible was weighed (W1) after being dried at 105°C for 1 h in hot air oven. The sample (2 g) was added and weighed (W2). The contents were first charred at 250°C for 1 h in hot plate and ashing at 550°C for 5 hours in muffle furnace. Then crucible was cooled in desiccator. The weight of crucible with ash was taken (W3).
Ws = Crucible plus ash sample.
W1 = Weight of crucible.
W2 = Sample plus crucible weight.
Crude lipid
The Soxhlet extraction method was used for crude lipid estimation. 200 ml of petroleum ether was used to extract sample (5 g) (Ws). Weight of empty round bottom flask in soxhlet unit was taken (W1). A thimble was made out of filter paper and sample was added. After addition of solvent, the soxhlet run for 24 hours until there was no more lipid content in sample. After extraction, the flask was placed inside oven at 110°C for 30 mins. After drying weight of flask with fat was taken (W2).
Ws = Weight of sample.
W1 = Weight of round bottom flask.
W2 = Weight of flask after drying.
Crude fiber
The amount of dietary fibre was determined using an adaptation of acid/base digestion method. 5 g (Ws) of sample was taken after being digested with 100 ml of 0.25 M sulfuric acid by heating for 30 minutes on a hot plate. Using 100 ml of 0.31 M sodium hydroxide solution, the process was repeated. After cooling in desiccator and being dried in oven at 100°C, weighed (W1). The sample was burned for 5 hours at 550°C in muffle furnace and weighed (W2).
Ws = Weight of sample.
W1 = Weight of fiber residue after drying.
W2 = Weight of residue after burning.
Crude protein
The protein content was estimated by micro Kjeldahl method. 20 ml of concentrated H
2SO
4 and Kjeldahl digestion tablet were boiled along with sample (2 g) until clear mixture was produced. The digest was filtered into volumetric flask of 250 ml. 50 ml of 45% NaOH solution added to prepared digest, was then steam-distilled to extract ammonia. The distillate (150 ml) was collected into conical flask containing 100 ml of 0.1 N Hcl. The collected distillate was back titrated against 0.1N Hcl with methyl orange as an indicator.
Crude protein % = N% × factor
N% = Nitrogen %
Factor = 6.25 ( standard factor)
Nitrogen % can be calculated by
V1= Volume of Hcl consumed.
Ws= Sample weight.
n1= Normality of HCl.
F1= Acid factor.
MWn= Molecular weight of nitrogen.
Total carbohydrate
The amount of carbohydrates calculated by subtracting amount of crude protein, crude fibre, ash and lipid from the total amount of dry matter.
Total carbohydrate = 100 - (% Moisture content + % Total Ash + % crude fat + % crude fibre + % crude protein).
Energy content
The caloric value was determined by multiplying values for crude protein, crude fat and carbohydrate by the standard Atwater factors: 4, 9 and 4 k cal, respectively.
Energy (kcal/100 g) = (Crude protein × 4) + (Crude fat × 9) + (Total carbohydrate × 4)
Antioxidant activity
The antioxidant activity was measured using DPPH technique. The plant extracts were prepared using methanol. 1 ml of methanol was added to extract and 1 ml of DPPH was added to each tube. DPPH in methanol solution without sample was taken as control. The solution’s absorbance was measured at 517 nm after 30 minutes of incubation in dark.
Statistic evaluation
Data was analysed using WASP (Web Agri Stat Package) statistical software which was developed by Agricultural Knowledge Management Unit (AKMU), Ela, Old Goa. The persual of data revealed that there was significant difference among the different flowers for its proximate content and antioxidant activity.