Jenny Ruales

Three underutilised sources of starch from the Andean region in Ecuador Part I. Physico-chemical characterisation

The physico-chemical aspects of three native Andean starches from Arracacha xanthorriza, Canna edulis and Oxalis tuberosa were investigated. Scanning electron microscopy-investigations showed that granules of A. xanthorriza were the smallest with irregular shape and sizes between 7 and 23 pm, whereas granules of O. tuberosa and C. edulis were both ovally shaped with granular sizes between 20 and 55 mum and 35-101 mum, respectively. All three starches revealed a B-type X-ray diffraction pattern. The gelatinisation behaviour was investigated using differential scanning calorimetry (DSC). The gelatinisation enthalpy was 14.6 J/g of starch for O. tuberosa, 15.7 J/g for C. edulis and 17.6 J/g for A. xanthorriza, and the peak temperature of the endothermic DSC-transition was 55.9, 61.2 and 60.1 degreesC, respectively. The amylose content determined by gel permeation chromatography after debranching with isoamylase was 4% for A. xanthorriza, 18.4% for O. tuberosa. and 23.8% for C. edulis. The amylopectin showed different structures among the three starches with a beta-amylolysis limit of 67.6% for C edulis, 64.5% for O. tuberosa and 56.6% for A. xanthorriza. The average chain length of the amylopectin was highest for A. xanthorriza (22.6), followed by O. tuberosa with 22.4, and lowest for C. edulis (21.9). The complexation ability of the three starches was investigated by adding sodium dodecyl sulphate (SDS), and the amylose content was positively correlated with the enthalpy of the amylose-SDS complex

Comparison of different methods for deacidification of clarified passion fruit juice

Abstract The high acidity of passion fruit limits its addition in food preparation. In order to easy the uses of this juice to formulate high aroma and flavour products, its citric acid content must be decreased. Various methods such as calcium salts precipitation, ion-exchange resins and electrodialysis with homopolar and bipolar membranes were investigated to increase the pH of a clarified passion fruit juice from 2.9 to 4.0. Each deacidification process was compared in terms of characteristics of deacidified juices such as concentration of inorganic and organic ions, colour and flavour. The deacidification by precipitation using CaCO 3 was not recommended because of CO 2 release. The ion-exchange process gave a poor quality juice in terms of organoleptic characteristics. Electrodialysis with homopolar membranes induced an increase in the sodium concentration. Precipitation with Ca(OH) 2 and electrodialysis with bipolar membrane were the most suitable processes in terms of sensorial properties of juices treated. The physico-chemical analyses showed an increase in the calcium concentration with the use of Ca(OH) 2 that could cause some precipitation problems in the final product. Inorganic anions were eliminated together with citrate by using electrodialysis and resins. Nevertheless, electrodialysis with bipolar membranes presented great advantages: it was a continuous process without reagent addition moreover allowing the production of a valuable solution of citric acid.

Phenolic Compounds in Rosaceae Fruits from Ecuador

RP-HPLC-DAD was used to study the content of phenolic compounds in four Ecuadorian fruits (strawberry, Andean blackberry, plum, and capuli cherry). Compounds were identified using spectral characteristics of representative standards and reference samples. Further, LC-MS with MS/MS was used to confirm molecular assignments in previously unstudied capuli cherry. Gallic acid was detected in Andean blackberry, and galloyl esters were detected in strawberries. Both these berries contained ellagic acid derivatives as major compounds, followed by anthocyanins, cyanidin, and pelargonidin glycosides. Plums and capuli cherry showed similar profiles of phenolic compounds, with chlorogenic and neochlorogenic acids being the most important hydroxycinnamates. (-)-Epicatechin was found in high amounts in Andean blackberry, plums, and capuli cherry, while (+)-catechin was only found in capuli cherry. Proanthocyanidins were major compounds in all fruits, and all contained considerable amounts of quercetin derivatives and smaller amounts of kaempferol derivatives. LC-MS analysis of capuli cherry revealed dimeric and trimeric procyanidins, quercetin and kaempferol hexosides and pentosides, and a kaempferol-O,C-dipentoside.

Bone-bound enzymes for food industry application

Abstract The immobilisation of β-galactosidase and amyloglucosidase (AMG) by means of physical adsorption on to bone powder is described. The influence of the enzyme load, applied to the support on immobilisation, yield and efficiency, has been determined. The immobilisation process improved the thermal stability of β-galactosidase (at 37°C), while immobilised AMG displayed a stability (at 55°C) similar to that of the soluble enzyme. The apparent KM (Kapp) values have been determined for both derivatives, for the β-galactosidase derivative KM was 3 mM using the artificial substrate ONPG and, for the AMG derivative, it was 1 mg/ml using soluble starch as substrate. The extent of lactose hydrolysis achieved, batchwise, with β-galactosidase derivatives acting on lactose buffered solutions, whey, whey permeates and skimmed milk, was in the range of 90% and decreased to 50% after 3 reuses. The conversion of 30% (w/v) liquefied cassava starch achieved with the AMG derivative was 98% until the 11th reuse, and over 95% until the 20th reuse.

Processing of quinoa (Chenopodium quinoa, Willd): effects on in vitro iron availability and phytate hydrolysis

The effect of different processing techniques was studied on in vitro iron availability and phytate hydrolysis in high and low saponin content quinoa (Chenopodium quinoa, Willd) seeds. Water slurries of ungerminated and germinated quinoa flour were processed by cooking, soaking, and fermentation using Lactobacillus plantarum as starter. Iron solubility under physiological conditions (in vitro) was measured and used as an estimation of iron availability. Phytate (inositol hexaphosphate/IP6) and its degradation products were analysed by an HPLC method. The IP6 + IP5 content was reduced by cooking with 4 to 8%, germination with 35 to 39%, soaking with 61 to 76% and by fermentation with 82 to 98%. The highest reduction, about 98%, was obtained after fermentation of the germinated flour. Cooking had no effect on the amount of soluble iron. Iron solubility increased, however, two to four times after soaking and germination, three to five times after fermentation and five to eight times after fermentation of the germinated flour samples and was highly correlated to the reduction of IP6 + IP5 (P < 0.001). There was no difference between the quinoa varieties with regard to phytate reduction and iron solubility. The pH in fermented samples was reduced from 6.5 to about 3.5, due to lactic acid formation.

Chemical composition and phenolic compound profile of mortiño (Vaccinium floribundum Kunth).

The phenolic compounds in mortiño (Vaccinium floribundum Kunth, family Ericaceae) from the páramos of Ecuador were studied by LC-DAD-MS/MS for the first time. (-)-Epicatechin, one dimer A and one trimer A were found at a total concentration of 18 mg/100 g FW. Of the flavonol glycosides (38 mg/100 g FW), quercetin and myricetin were found as -3-O-hexosides, -3-O-pentosides and -3-O-deoxyhexosides. Chlorogenic and neochlorogenic acids together with caffeic/ferulic acid derivatives were found as predominant components among the hydroxycinnamic acids in the berry. Anthocyanins, including cyanidin and delphinidin derivatives, were the major phenolic compound class quantified (345 mg cyanidin-3-O-glucoside/100 g FW).

Physical and chemical characteristics of golden-yellow and purple-red varieties of tamarillo fruit (Solanum betaceum Cav.)

Golden-yellow and purple-red tamarillos (Solanum betaceum Cav.) cultivated in Ecuador were studied for their physical properties, proximate composition, pH, °Brix, acidity, sugars, organic acids, minerals, vitamin C and β-carotene content in the edible part. Results were compared with those for Spanish fruits. The golden-yellow and purple-red Ecuadorian fruits were larger (107 and 188 g) than the respective Spanish fruits (43 and 63 g), softer but generally similar in chemical composition except for fat (0.72 and 0.6%) and malic acid (0.32 and 0.53%) contents in the golden-yellow and purple-red Ecuadorian fruits. Tamarillo fruits are a good source of potassium (~400 mg/100 g fresh weight). Total phenolics in the golden-yellow and purple-red varieties were 125 and 187 mg gallic acid equivalents/100 g fresh weight, respectively. The golden-yellow variety had weaker anti-DPPH radical activity than the purple-red variety. Flavonols were only found in the peel of both varieties, while hydroxycinnamic acid derivatives were found in peel and pulp.

The nutritional quality of an infant food from quinoa and its effect on the plasma level of insulin-like growth factor-1 (IGF-1) in undernourished children

An infant food product was manufactured by drum drying a pre-cooked slurry of quinoa (Chenopodium quinoa, Willd) flour. The chemical composition shows that the product is a potential source of valuable nutrients, like protein (16%), vitamin E (19 mg/kg), thiamine (0.7 mg/100 g), iron (70 mg/kg), zinc (48 mg/kg) and magnesium (1.8 g/kg), all the values expressed on dry basis, to pre-school children (of 5 years of age). The animal feeding experiments with rats showed a net protein utilisation (NPU) of 68, digestibility (TD) 95 and biological value (BV) 71. The level of insulin-like growth factor-1 (IGF-1) in the plasma of the children who consumed a supplementary portion of 2 × 100 g of the above infant food product showed an increase after a period of 15 days, while the plasma level of IGF-1 in the children of the control group as well as the reference group did not show any significant increase.

Biocatalytic properties of lipase in crude latex from babaco fruit (Carica pentagona)

Biocatalytic activities in proteolysis, lipolysis and interesterification reactions were studied for crude latex from the subtropical plant Carica pentagona. The results reveal that crude Carica pentagona latex exhibits equivalent proteolytic activities (5.73 units mg−1) and lipolytic activities (1.01 units mg−1) compared to the well-known Carica papaya, the commercially source for papain (4.57 units mg−1 and 0.90 units mg−1 respectively). Therefore, in interesterification reactions, Carica pentagona latex shows interesting lipase properties (0.77 units mg−1) higher than commercial Carica papaya latex (0.28 units mg−1).

Deacidification of the clarified passion fruit juice (#P. edulis# f. #flavicarpa#)

The high acidity of passion fruit limits its addition in food preparation and gives poor aroma and flavour products. The reduction of the acidity of the fruit juice can avoid this problem. Various methods such as calcium precipitation, ion-exchange resins and electrodialysis (ED) with homopolar and bipolar membranes (BMs) were investigated to deacidify yellow passion fruit juice. The pH of the juice was increased from 2.9 to 4.0. Calcium hydroxide and ED with BM are the most suitable processes in terms of physicochemical and sensorial analyses.