Starch

A total of five traditional fruit Korean wine types produced from maesil (Prunus mume), black raspberry (Rubus coreanus Miquel), peach (Prunus persica), apple (Malus domestica), and plum (Prunus salicina), as well as two types of imported red and white grape wines were purchased from local markets in Korea. Maesil wine is made from Prunus mume, which is commonly known as Japanese apricot or maesil in Korea. Black raspberry wine is made from Rubus coreanus Miquel, commonly known as Bokbunja in Korea. Red and white grape wine is made from Vitisvinifera. Ethyl carbamate (98% purity), butyl carbamate (98% purity), isonicotinic acid, potassium dihydrogen phosphate, sodium bisulfate (NaHSO₃), thiosulfate solution (Na₂S₂O₃), iodine solution (I₂), tartaric acid, acetone, 1,2-diaminobenzene, diacetyl (2,3-butanedione, 99% purity), and 2,3-hexanedione (96% purity) were purchased from Sigma-Aldrich Co. Ltd. (St. Louis, MO, USA). Disodium hydrogen phosphate, chloramin T, and starch were purchased from Daejung Chemicals & Metals Co., Ltd. (Siheung, Korea). 3-methyl-1-phenyl-5-pyrazolone (pyrazolone), acetic acid, and phenolphthalein were obtained from Samchun Pure Chemicals Co., Ltd. (Pyeongtaek, Korea). Other solvents and reagents used were of analytical grade.

All the materials viz. polyvinyl alcohol (Mw = 1500 amu, Sigma-Aldrich, Darmstadt, Germany), N-(3-bromopropyl)phthalimide (Sigma-Aldrich, Darmstadt, Germany), silver nitrate (BDH, England), Starch (Daejung, Korea), glycerin Starch (Daejung, Korea), NaOH (Sigma-Aldrich, Darmstadt, Germany), sodium citrate (Sigma-Aldrich, Darmstadt, Germany), sodium borohydride (Sigma-Aldrich, Darmstadt, Germany) DMF (N,N-dimethylformamide) (Daejung, Korea), ethanol (Daejung, Korea), hydrazine (Daejung, Korea), isopropyl alcohol (Daejung, Korea) and chloroform (Daejung, Korea) were obtained from the commercial sources. All solvents including deionized water were of analytical grade and were used without further purification.

Starch, polyvinyl alcohol, gelatin, gum arabic, paraffin wax, concentrated hydrochloric acid (33.5%) and p-dimethyl amino benzaldehyde of laboratory grade were obtained from Daejung Chemicals & Metals Co., Korea. Molasses was provided by Almoiz Sugar Mills Unit II, Dera Ismail Khan, Pakistan. Commercial grade urea granules were purchased from a local market and contained 46% nitrogen content (Fauji Fertilizer Bin Qasim Limited, Sindh, Pakistan). Urea was sieved to get uniform sized particles of 4 mm. All chemicals were utilized without any further purification.