Browsing by Author "Malpiedi, Luciana Pellegrini"
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- Continuous method to determine the trypsin inhibitor activity in soybean flourPublication . Coscueta, Ezequiel R.; Pintado, Manuela E.; Picó, Guillermo A.; Knobel, Gastón; Boschetti, Carlos E.; Malpiedi, Luciana Pellegrini; Nerli, Bibiana B.The determination of trypsin inhibitor (TI) activity is of importance to evaluate the nutritional value of soybean flours. An analytical method, which involves a continuous spectrophotometric rate determination for trypsin activity against the substrate N-benzoyl-DL-arginine p-nitroanilide, is proposed as an alternative to the standard discontinuous assay. Stopping the reaction with acetic acid and a centrifugation/filtration step to decrease turbidity are not required, thus reducing costs and sample preparation time. The TI activity of different flour samples, determined by both assays, demonstrated to be statistically comparable, irrespective of the TI concentration level. The coefficients of variation of the novel method did not exceed 8% at any concentration level. The curves of progress reaction showed a non-linear behavior in samples without TI. A reduction of incubation time from 10min to 2min increased the method sensitivity and extended its linear range. A more economical, faster and simpler assay was developed.
- Non-ionic aqueous micellar extraction of trypsin inhibitors and isoflavones from soybean meal: process optimizationPublication . Coscueta, Ezequiel R.; Brassesco, María Emilia; Malpiedi, Luciana Pellegrini; Nerli, BibianaSimultaneous extraction of trypsin inhibitors and soy isoflavones from soybean meal was investigated using the non-destructive phytochemical extraction process, namely aqueous micellar system. The ethoxylated aliphatic alcohols Genapol X-080, Tergitol 15-S-7, and Tergitol 15-S-9, all non-toxic and biodegradable surfactants, were assessed as potential extractants. A Box-Behnken multifactorial design with the application of the Derringer desirability was used to determine the conditions that maximized the trypsin inhibitors and isoflavone extraction while minimizing the protein extraction. The optimum condition of 5% m/m of surfactant in 50 mM aqueous sodium citrate solution pH 4.5, at 45 °C for 45 min, was established for the three surfactants. The novel methodology would allow the extraction of the main soybean antinutritional factors, trypsin inhibitors, and the valuable isoflavones, preserving the nutritional quality of the treated material. This represents a sustainable alternative methodology for industrial purposes due to its low cost, biodegradability, non-toxicity, and easy scaling up.
- Production of soy protein concentrate with the recovery of bioactive compounds: from destruction to valorizationPublication . Coscueta, Ezequiel R.; Malpiedi, Luciana Pellegrini; Pintado, Maria Manuela; Nerli, Bibiana B.This work aimed to develop a novel methodology based on aqueous micellar systems (AMS), for producing soy protein concentrates (SPC) from soybean flour and recovering high-valuable bioactive compounds as by-products. Ethoxylated aliphatic alcohols Tergitol 15-S-7 and Tergitol 15-S-9, non-toxic and biodegradable surfactants, were selected to form the AMS. The methodology consisted of an extractive stage of soybean flour with AMS, which rendered both a pellet, i.e., the SPC, and a supernatant containing the extracted bioactive compounds. The latter was further heated above the cloud point temperature, thus resulting in a biphasic system formed by a micelle-rich phase (MP) and an aqueous phase (AP). Obtained SPC showed a noticeable loss (∼90%) of trypsin inhibitor activity, a total protein content close to 60%, soluble protein amounts varying from 19% to 34%, and remarkable released (by simulated digestion) antioxidant and antihypertensive activities. Those indicators are similar to or even better than those corresponding to SPC from the classical acid-extraction method. The AMS also exhibited an enhanced efficiency for extracting antinutrients such as non-digestible oligosaccharides, trypsin inhibitors, and lectins mostly recovered at the AP and separated from isoflavones, which were concentrated and isolated at the MP. The recovery of all the mentioned bioactive compounds, whether beneficial or undesirable, broadens their uses in research, food, and pharmacological fields. This successful performance, simplicity, scalability, and sustainability make the proposed AMS-based extraction a powerful tool for processing plant derivatives and valorizing their by-products.