TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: Unsaturated fatty acid(s) comprises 3-36C monounsaturated or polyunsaturated fatty acid chosen from butenoic, pentenoic, hexenoic, pentenoic, octenoic, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, palmitoleic acid, oleic acid, ricinoleic acid, vaccenic acid, linoleic acid, linolenic acid, eicosapentaenoic acid, behenic acid and erucic acid. Saturated fatty acid(s) is 3-36C saturated fatty acid chosen from propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecyclic acid, arachidic acid, heneicosylic acid, behenic acid, tricosylic acid, lignoceric acid, pentacoyslic acid, cerotic acid, heptacosylic acid, carboceric acid, montanic acid, nonacosylic acid, melissic acid, lacceroic acid, psyllic acid, geddic acid, and ceroplastic acid. The biodiesel crystallization depressant composition further contains biodiesel fuel comprising saturated fatty acid methyl ester, monounsaturated fatty acid methyl ester and/or polyunsaturated fatty acid methyl ester. Saturated, monounsaturated or polyunsaturated fatty acid methyl ester is methyl palmitate, methyl laurate, methyl myristate, methyl caprate, methyl linoleate, methyl linolenate, methyl oleate, methyl stearate, methyl arachidate and/or methyl behenate, preferably methyl palmitate or methyl stearate. Triacylglycerol preferably comprises 1,3-dioleoyl-2-palmitoyl glycerol or 2-steroyl diolein. 1,3-Dioleoyl-2-palmitoyl glycerol and methyl palmitate, or 1,3-dioleoyl-2-palmitoyl glycerol and methyl stearate, are mixed in a desired molar fraction of Xopo, where X is 0-1. 2-Stearoyl diolein and methyl stearate are mixed in a desired molar fraction of Xoso, where X is 0-1. The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl palmitate comprises two differential scanning calorimetric (DSC) cooling and/or heating cycle eutectics at molar fraction of 0.45opo and 0.8opo. The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl stearate comprises a singularity at 0.65opo and 0.90opo. The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl stearate comprises a DSC heating cycle eutectic at molar fraction of 0.90opo. The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl stearate comprises a DSC heating cycle peritectic at molar fraction of 0.65opo, with a DSC heating cycle peritectic line spanning from molar fraction 0.11opo to molar fraction 0.65opo. The mixture of 2-stearoyl diolein and methyl stearate comprises a molar fraction of 0.65oso to 1oso, where the mixture comprises a crystallization primarily in an orthorhombic form. The mixture of 2-stearoyl diolein and methyl stearate comprises a molar fraction of 0oso to 0.65oso, where the mixture comprises a crystallization primarily in a triclinic form and a monoclinic form. The mixture of 2-stearoyl diolein and methyl stearate has two DSC heating cycle eutectics at molar fraction of 0.50oso and 0.8oso. Alternately, the biodiesel crystallization depressant composition comprises triacylglycerol comprising saturated fatty acid(s) or trans-unsaturated fatty acid(s) in sn-1 position, and unsaturated fatty acid(s) in sn-2 and sn-3 positions, or triacylglycerol comprising saturated fatty acid(s) in sn-3 position and saturated fatty acid (s) or trans-unsaturated fatty acid(s) in sn-1 and sn-2 positions. Preferred Properties: The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl palmitate has a calculated liquidus line comprising a nonideality of mixing parameter of -62.54 kJ/mol to 0.68 kJ/mol, an enthalpy of melting of 24-161 kJ/mol, and a melting temperature of 293-303 degrees K. The mixture of 1,3-dioleoyl-2-palmitoyl glycerol and methyl stearate has a calculated liquidus line comprising a nonideality of mixing parameter of -97.1 kJ/mol to -3.5 kJ/mol, an enthalpy of melting of 72.89-195.69 kJ/mol, and a melting temperature of 19-38 degrees C. The mixture of 2-stearoyl diolein and methyl stearate has a calculated liquidus line comprising a nonideality of mixing parameter of -49.5 kJ/mol to -7, an enthalpy of melting of 53.22-76.14 kJ/mol, and a melting temperature of 294-310 degrees K.