tent using the method described by
Ma and Crattner (1970). Removal of cationic interferences prior to analysis
was necessary. This was done by adding 0.15 g of cation-exchange resin
(Amberlite IR-120 [H+]) to solutions of samples, stirring for 20
min, and removal of an aliquot after settling (Hoffer et al. 1979).
Emulsions were prepared with a Vibra Cell Sonifier (Sonics & Materials,
Inc.). A mixture of either limonene or olive oil (0.25 ml), and gum solution
(2.25 ml of a 1% w/v solution) was sonicated for two 90-s periods, first
placing the tip of the instrument's tapered probe into the surface of the
mixture, and then lowering the probe into the middle of the sample. The
instrument was used in a continuous mode at a power setting of 3 (75 watts)
(Dea and Madden 1986). In the case of diluted emulsions, 1 ml of emulsion was
diluted with 9 ml of distilled water (1:10 dilution). After 2 min, another
1:10 dilution was made (1:100 dilution) (Prakash et al. 1990).
Emulsion stability was determined by diluting the emulsion and monitoring
turbidity as a function of time at a wavelength of 500 nm with a Varian Model
DMS80 double-beam spectrophotometer (Pearce and Kinsella 1978). Gum arabic was
used as a standard. All three emulsions were diluted appropriately to give a
final 1:1000 dilution.
Marigold flower petal meal contains a water-soluble gum (MFP) that has been
characterized as a protein-polysaccharide. MFP has emulsifying and
emulsion-stabilizing properties equivalent to those of gum arabic towards
limonene and slightly less than those of gum arabic towards olive and castor
oils. It is, however, not possible to prepare concentrated emulsions with MFP
because of the high viscosity of its solutions at concentrations above about
5%. A test of the hypothesis that the reason for the difference in rheological
behavior between MFP and gum arabic, also a protein-polysaccharide, was the
much lower charge density of MFP did not support it for increasing the anionic
charge on MFP to a value close to that of gum arabic reduced its viscosity only
- Abid, M. and M.A. Maqbool. 1990. Effects of inter-cropping of Tagetes
erecta on root-knot disease and growth of tomato. Int. Nematol. Network
- Alam, M.M., A.M. Khan, and S.K. Saxena. 1988. Management of plant parasitic
nematodes by different cropping sequences. Indian J. Plant Pathol.
- Anuradha, K., K. Pampapathy, and N. Narayana. 1988a. Effect of N and P2O5 on
the nutrient composition and uptake by marigold (Tagetes erecta L.). S.
Indian Hort. 36:209-211.
- Anuradha, K., K. Pampapathy, and R. Sreenivasalu. 1988b. Effect of N and P2O5
on flowering and yield of marigold (Tagetes erecta L.). S. Indian Hort.
- Anuradha, K., K. Pampapathy, and N. Narayana. 1990. Effect of nitrogen and
phosphorus on flowering, yield and quality of marigold. Indian J. Hort.
- Arora, J.S. and K. Khanna. 1986. Effect of nitrogen and pinching on growth
and flower production of marigold (Tagetes erecta). Indian J. Hort.
- Arulmozhiyan, R. and C.M. Pappaiah. 1989. Studies on the effect of nitrogen,
phosphorus and ascorbic acid on the growth and yield of marigold (Tagetes
erecta L.) cv. MDU 1. S. Indian Hort. 37:169-172.
- Baghel, P.P.S. and D.C. Gupta. 1986. Effect of intercropping on root-knot
nematode (Meloidogyne javanica) infesting grapevine (var. Perlette).
Indian J. Nematol. 16:283-284.
- BeMiller, J.N., A.K. Gupta, and D.S. Wickramasingha. 1989. Structure and
properties of the water-extractable polysaccharide of marigold (Tagetes
erecta) petals, p. 1-14. In: R.P. Millane, J.N. BeMiller, and R.
- Chandrasekaran (eds.). Frontiers in carbohydrate research-1. Elsevier Applied
- Dea, I.C.M. and J.K. Madden. 1986. Acetylated pectic polysaccharides of sugar
beet. Food Hydrocolloids 1:71-88.
- Girwani, A., R.S. Babu, and R. Chandrasekhar. 1990. Response of marigold
Tagetes-erecta to growth-regulators and zinc. Indian J. Agr. Sci.
- Gowda, J.V.N. and R. Jayanthi. 1986. Studies on the effect of spacing and
season of planting on growth and yield of marigold Tagetes erecta Linn.
S. Indian Hort. 34:198-203.
- Hoffer, E.M.