Nurhan Arslan

Production of carboxymethyl cellulose from sugar beet pulp cellulose and rheological behaviour of carboxymethyl cellulose

The sugar beet pulp cellulose was converted carboxymethyl cellulose (CMC) by etherification and the process of carboxymethylation was optimised with respect to the solvent medium, alkali concentration, sodium chloroacetate amount, temperature and time of reaction. The optimised product had a DS of 0.6670 and the optimum conditions for carboxymethylation were sodium chloroacetate amount of 3.0 g, an NaOH concentration of 30%, temperature of 70 °C, time of 360 min with isobutyl alcohol as the solvent medium. The flow behaviour of CMC from sugar beet pulp cellulose was determined using a rotational viscometer for concentration range of 10–30 kg/m3, temperature range of 20–30 °C, and shear rate range of 3.24–64.8 s−1. Newtonian, Bingham and power law models were applied to fit the flow behaviour of CMC solutions. The behaviour of CMC solutions was pseudoplastic and the flow behaviour of CMC solutions was found to be most adequately described by the power-law model. Concentration, temperature and shear rate affected the rheological properties. The temperature dependency of the consistency coefficient and the flow behaviour index was modelled using a Turian approach. Both the consistency coefficient and the flow behaviour index were sensitive to changes in temperature and concentration. The consistency coefficient varied between 0.0024 and 0.0162 whereas the flow behaviour index varied between 0.7017 and 0.9590. The flow behaviour index decreased with concentration and increased with temperature, while the opposite trend was observed with the consistency coefficient. The apparent viscosity decreased with increasing temperature and shear rate implying that CMC solutions studied behaved as shear thinning. The experimental data were fitted by mathematical models to allow prediction of the consistency coefficient, the flow behaviour index and the apparent viscosity as a function of temperature and concentration.

Carboxymethyl cellulose from sugar beet pulp cellulose as a hydrophilic polymer in coating of mandarin

Sugar beet pulp cellulose was converted carboxymethyl cellulose (CMC) by etherification. The coating of mandarin surfaces with films formed by different emulsions containing CMC from sugar beet pulp cellulose as a hydrophilic polymer was carried out. Paraffin wax, beeswax and soybean oil; CMC with degree of substitution of 0.6670; Emulgin PE, triethanolamine, oleic acid and sodium oleate were used as hydrophobic phases, hydrophilic polymer and emulsifying agents in the coating of mandarins to extend postharvest life and to maintain their quality, respectively. Mandarins were stored in a storage chamber at 25 °C and at a relative humidity of 75%. Samples were taken at regular intervals for analysis. The changes in weight loss, pH, soluble solids, titratable acidity and ascorbic acid of the coated samples with storage time were investigated in comparison with the uncoated samples to determine the delay in the deterioration time of the samples. The effect of CMC as a hydrophilic polymer in coating emulsions on weight loss, pH, soluble solids, titratable acidity and ascorbic acid was also studied. The modified drying models describing the storage time dependence of weight loss were fitted to the experimental data and the model parameters in the equations were determined by multiple regression analysis. The coatings contributed to a lower reduction in pH. The coatings decreased the soluble solids and titratable acidity loses in comparison to the uncoated mandarins. The coating of mandarins delayed ascorbic acid loss. It was possible to extend the storage period with lower weight loss until 27 days by coating mandarin surfaces with emulsions containing CMC from sugar beet pulp cellulose as a hydrophilic polymer. It was found that the emulsion prepared using the mixture of soybean oil, CMC, sodium oleate and water was suitable for the coating of mandarins.

Mathematical model for prediction of apparent viscosity of molasses

Abstract The rheological properties of molasses with or without added ethanol were studied using a rotational viscometer at several temperatures (45–60 °C), different amounts of added ethanol in molasses–ethanol mixture per 100 g of molasses (1–5%) and rotational speed ranging from 4.8 to 60 rpm. Flow behaviour index of less than one confirmed pseudoplasticity ( n =0.756–0.970). The power law model was found to be the appropriate to fit the flow curves of molasses. The consistency coefficient decreased with the amounts of added ethanol, while the flow behaviour index increased with the amounts of added ethanol. The consistency coefficient decreased with temperature but no harmonious variation was observed in the flow behaviour index values with increase in temperature. The apparent viscosity decreased with increasing temperature and shear rate, implying that molasses with or without added ethanol studied behaved as shear thinning. The mathematical models were developed for determining the apparent viscosity of molasses as affected by temperature and added ethanol. The suitability of the models relating the apparent viscosity were judged by using various statistical parameters such as the mean percentage error, the mean bias error, the root mean square error, the modelling efficiency and chi-square ( χ 2 ).

Extending shelf-life of peach and pear by using CMC from sugar beet pulp cellulose as a hydrophilic polymer in emulsions

Peach and pear were treated with different compositions of emulsions to extend shelf-life of fruits and to preserve the fruit quality. Paraffin wax, beeswax and soybean oil; carboxymethyl cellulose (CMC) with degree of substitution of 0.6670; Emulgin PE, triethanolamine, oleic acid and sodium oleate were used as hydrophobic phases, hydrophilic polymer and emulsifying agents in the coatings of peach and pear, respectively. The CMC obtained by etherification of the sugar beet pulp cellulose was used as a hydrophilic polymer. To investigate the post-harvest water loss of peach and pear, fruits were observed during storage while being subjected to dehydrating conditions in storage chamber at 25 °C and 75% relative humidity level. The changes in weight, pH, soluble solids, titratable acidity and ascorbic acid of the coated samples with storage time were measured at regular intervals throughout the storage period to evaluate the effect of storage period on fruit quality. The modified drying models describing the storage time dependence of weight loss were fitted to the experimental data and the model parameters in equations were determined by multiple regression analysis. Some of the coatings decreased the soluble solids, titratable acidity and ascorbic acid losses in comparison to the uncoated peaches and pears. The coating of peach and pear surfaces with emulsions containing CMC from sugar beet pulp cellulose as a hydrophilic polymer extended the shelf-lives of peach and pear to 12 and 16 days, respectively. It was found that a combination using beeswax as hydrophobic phase, triethanolamine and oleic acid as emulsifying agent, CMC as hydrophilic polymer and the emulsion containing soybean oil as hydrophobic phase, sodium oleate as emulsifying agent, CMC as hydrophilic polymers were suitable for the coating of peaches and pears, respectively.

Filtration of sugar-beet pulp pectin extract and flow properties of pectin solutions

Sugar-beet pulp pectin extract was vacuum filtered at 25 °C and different filtration pressures (0.20 × 105, 0.33 × 105 and 0.47 × 105 Pa). The measurement of the average specific cake resistance was discussed. The specific cake resistance was dependent on the filtration pressure. The cake compressibility coefficient at 25 °C was calculated as 0.389. The correlation between the pressure drop and the average specific cake resistance showed that sugar-beet pectin forms a compressible filter cake. By using kieselguhr as a filter aid to increase the filtration efficiency, the effects of varying the precoating amount and the filter aid dose on the average specific cake resistance of cake at a constant pressure filtration were studied. The effects of temperature and concentration on the viscosity of pectin solutions were examined at six different temperatures between 20 and 70 °C and four concentration levels between 0.005 and 0.020 kg l−1. The activation energy for viscous flow was in the range 6.69–13.46 kJ mol−1. Equations describing the combined effects of temperature and concentration on the viscosity are given.

Filtration of pectin extract from grapefruit peel and viscosity of pectin solutions

Abstract The yield of pectin extracted (85 °C, pH = 2.5, 90 min) by acidified water in a ratio of 25 parts per part of dry peel from dried grapefruit peel was 21.1% (DM basis). The pectin extract was vacuum filtered at different temperatures and under various pressure differences, and the average specific cake resistances were determined. The specific cake resistance was highly dependent on the filtration pressure. The cake compressibility coefficients at 15 °C, 25 °C and 35 °C were calculated as 0.387, 0.379 and 0.379, respectively. The filtration rate observed at 15 °C was higher than that at 25 °C due to flocculation at low temperature. The effects of temperature and concentration on the viscosity of pectin solutions were examined at six different temperatures between 10 °C and 60 °C and four concentration levels between 0.3 g/100 ml and 1.4 g/100 ml. The activation energy for viscous flow was in the range 2·10–3·77 kcal mol−1. Finally, the combined effect of temperature and concentration on the viscosity was expressed as η = 8.52 × 10 −5 exp( −1.6162 C + 1.807 exp(0.5493 C) RT )