Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA)

El CIDCA es una Unidad Ejecutora en el área de Ciencia, Tecnología e Ingeniería de Alimentos vinculada al Centro Científico Tecnológico CONICET La Plata (CCT-La Plata), a la Facultad de Ciencias Exactas de la UNLP y a la CICPBA. En el CIDCA se realizan tareas de investigación científica y tecnológica, formación de recursos humanos, trabajos de desarrollo, innovación y transferencia de tecnología, así como servicios técnicos al sector productivo y a las instituciones que así lo requieran.Academia de la Ingeniería de la provincia de Buenos Aire

Self-aggregation in pyrrole: matrix isolation, solid-state infrared spectroscopy and DFT

Pyrrole (C 4 H 5 N) was embedded in low-temperature solid inert matrixes (argon, xenon; T ) 9 K) and both the monomer and low-order aggregates characterized by FTIR spectroscopy. The spectroscopic studies were complemented by extensive theoretical [DFT(B3LYP)/6-311++G(d,p)] structural and vibrational studies carried out for the monomer and their self-aggregates (up to four units). The calculated spectrum for monomeric pyrrole fits well those obtained immediately after deposition (at 9 K) of diluted matrixes, which can be prepared keeping the compound at low temperature before deposition and using low fluxes of the sublimate. Annealing of the matrixes to higher temperatures or increasing of the gaseous flux during deposition leads to aggregation, which can be easily recognized spectroscopically. On the basis of the theoretically predicted spectra for the monomer, dimer, trimers, and tetramers of pyrrole, assignments were proposed for the experimentally observed bands. It was also found that the formation of the hydrogen-bonded clusters shows a significant cooperativity effect, which was studied in detail and could be related with several structural and spectroscopic parameters. Infrared spectra of the pure solid compound at low temperatures in both amorphous and crystalline states were also studied and interpreted

Valorization of okara oil for the encapsulation of <i>Lactobacillus plantarum</i>

Oil-in-water (O/W) emulsions of okara oil-caseinate (1:2; 1:3 and 1:4 O/W ratios) were used to encapsulate Lactobacillus plantarum CIDCA 83114. Once encapsulated, microorganisms were freeze-dried or spray-dried, and observed by scanning electronic and confocal microscopies. A physical characterization of the dehydrated capsules was carried out by determining their moisture content, water activity, particle size, polydispersity index and zeta potential. Determining the induction times and peroxide values provided information about their susceptibility to oxidation. In turn, bacterial stability was analyzed by plate counting before and after freeze-drying and spray-drying, and during storage at 4 °C. Spray-dried emulsions had lower Z-sizes and polydispersity indexes, higher induction times and lower peroxide values than the freeze-dried ones, thus resulting better systems to protect L. plantarum CIDCA 83114. In addition, the culturability of spray-dried bacteria did not decrease neither after spray-drying nor up to 60 days of storage at 4 °C. The results showed that the better physical-chemical stability of spray-dried capsules determined the greater stability of microorganisms. This demonstrates the importance of defining adequate emulsions’ formulations for an efficient encapsulation of microorganisms, with promising applications in the development of novel functional foods.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Valorization of okara oil for the encapsulation of Lactobacillus plantarum

Oil-in-water (O/W) emulsions of okara oil-caseinate (1:2; 1:3 and 1:4 O/W ratios) were used to encapsulate Lactobacillus plantarum CIDCA 83114. Once encapsulated, microorganisms were freeze-dried or spray-dried, and observed by scanning electronic and confocal microscopies. A physical characterization of the dehydrated capsules was carried out by determining their moisture content, water activity, particle size, polydispersity index and zeta potential. Determining the induction times and peroxide values provided information about their susceptibility to oxidation. In turn, bacterial stability was analyzed by plate counting before and after freeze-drying and spray-drying, and during storage at 4 °C. Spray-dried emulsions had lower Z-sizes and polydispersity indexes, higher induction times and lower peroxide values than the freeze-dried ones, thus resulting better systems to protect L. plantarum CIDCA 83114. In addition, the culturability of spray-dried bacteria did not decrease neither after spray-drying nor up to 60 days of storage at 4 °C. The results showed that the better physical-chemical stability of spray-dried capsules determined the greater stability of microorganisms. This demonstrates the importance of defining adequate emulsions’ formulations for an efficient encapsulation of microorganisms, with promising applications in the development of novel functional foods.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Okara: A nutritionally valuable by-product able to stabilize <i>Lactobacillus plantarum</i> during freeze-drying, spray-drying, and storage

Okara is a nutritionally valuable by-product produced in large quantities as result of soymilk elaboration. This work proposes its use as both culture and dehydration medium during freeze-drying, spray-drying, and storage of Lactobacillus plantarum CIDCA 83114. Whole and defatted okara were employed as culture media for L. plantarum CIDCA 83114. The growth kinetics were followed by plate counting and compared with those of bacteria grown in MRS broth (control). No significant differences in plate counting were observed in the three media. The fatty acid composition of bacteria grown in whole and defatted okara showed a noticeable increase in the unsaturated/saturated (U/S) fatty acid ratio, with regard to bacteria grown in MRS. This change was mainly due to the increase in polyunsaturated fatty acids, namely C18:2. For dehydration assays, cultures in the stationary phase were neutralized and freeze-dried (with or without the addition of 250 mM sucrose) or spray-dried. Bacteria were plate counted immediately after freeze-drying or spray-drying and during storage at 4°C for 90 days. Freeze-drying in whole okara conducted to the highest bacterial recovery. Regarding storage, spray-dried bacteria previously grown in whole and defatted okara showed higher plate counts than those grown in MRS. On the contrary, freeze-dried bacteria previously grown in all the three culture media were those with the lowest plate counts. The addition of sucrose to the dehydration media improved their recovery. The higher recovery of microorganisms grown in okara after freeze-drying and spray-drying processes and during storage was ascribed to both the presence of fiber and proteins in the dehydration media, and the increase in U/S fatty acids ratio in bacterial membranes. The obtained results support for the first time the use of okara as an innovative matrix to deliver L. plantarum. Considering that okara is an agro-waste obtained in large quantities, these results represent an innovative strategy to add it value, providing a symbiotic ingredient with promising industrial applications in the development of novel functional foods and feeds.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Applications of Infrared and Raman Spectroscopies to Probiotic Investigation

In this review, we overview the most important contributions of vibrational spectroscopy based techniques in the study of probiotics and lactic acid bacteria. First, we briefly introduce the fundamentals of these techniques, together with the main multivariate analytical tools used for spectral interpretation. Then, four main groups of applications are reported: (a) bacterial taxonomy (Subsection 4.1); (b) bacterial preservation (Subsection 4.2); (c) monitoring processes involving lactic acid bacteria and probiotics (Subsection 4.3); (d) imaging-based applications (Subsection 4.4). A final conclusion, underlying the potentialities of these techniques, is presented.Facultad de Ciencias Exacta

Nutritional and technological properties of a quinoa (<i>Chenopodium quinoa</i> Willd.) : Spray-dried powdered extract

The relevance of an appropriate nutrition requires innovation in the design of food ingredients. The goal of this work was to obtain a powdered extract of quinoa by using spray-drying. To this aim, quinoa flour was suspended in water to obtain a soluble fraction mainly composed of proteins, starch, fiber, lipids, antioxidants and minerals. The spray-drying conditions of this quinoa soluble fraction were set-up in terms of inlet temperatures (150, 160, 170 and 180 °C) and feed flow (4.5, 7.5, 10.5 mL/min). The obtained powders were characterized by determining the proximate composition, antioxidant activity, microstructure, fatty acids' profile, and starch and proteins' structures. A correlation among the drying parameters and the chemical and functional attributes of the powders was addressed using principal component analysis. From a technological viewpoint the use of moderate feed flows (7.5 mL/min) and high inlet temperatures (180 °C) was the best combination to obtain high powder yields (85% d.b.), low aw (0.047 ± 0.005) and high solids content (0.956 ± 0.005). The drying temperature positively affected the structure of starch, improving swelling and favoring moderate agglomeration which increases the encapsulation properties of quinoa. These results support the use of spray-drying as a suitable method to obtain powdered extracts of quinoa without affecting the nutritional value, thus supporting their use as functional ingredients in the formulation of ready-to-eat foods.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Novel Functional Whey-Based Drinks with Great Potential in the Dairy Industry

This work focuses on the production of liquid whey protein concentrates by ultrafi ltration followed by thermal denaturation and homogenization of the ultrafi ltrated concentrate, as well as on the production of ultrafi ltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafi ltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately aft er inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts aft er 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods.Facultad de Ciencias Exacta

Novel Functional Whey-Based Drinks with Great Potential in the Dairy Industry

This work focuses on the production of liquid whey protein concentrates by ultrafi ltration followed by thermal denaturation and homogenization of the ultrafi ltrated concentrate, as well as on the production of ultrafi ltrated permeates concentrated by reverse osmosis. Kefir grains (fresh and thawed) and/or commercial probiotic bacteria were inoculated in both liquid whey protein concentrates and concentrated ultrafi ltrated permeates and grown at 25 °C for 24 h for the manufacture of fermented drinks. The physicochemical characterization (pH, titratable acidity, viscosity, and content of total solids, ash, fat and proteins) of the obtained drinks was then assessed and compared. Enumeration of viable microorganisms was carried out immediately aft er inoculation (at 0 h), during the fermentation period (at 12 and 24 h) and during refrigerated storage (at 48, 168 and 336 h). The fermented drinks showed acceptable physicochemical and sensorial properties, and contained above 7 log CFU/mL of lactococci and lactobacilli and 6 log CFU/mL of yeasts aft er 14 days of refrigerated storage, which is in agreement with the standards required by international organizations like European Food Safety Authority (EFSA) and Food and Drug Administration (FDA) for products containing probiotics. In summary, the strategy developed in this work contributes to the expansion of the applications of products derived from whey fractionation for the design of novel functional foods.Facultad de Ciencias Exacta

Biophysical Methods for the Elucidation of the S-Layer Proteins/Metal Interaction

Surface-layers (S-layers) are macromolecular paracrystalline arrays of proteins or glycoproteins that can self-assemble into 2-dimensional semi-permeable meshworks to overlay the cell surface of many bacteria and archaea. They usually assemble into lattices with oblique, square or hexagonal symmetry and serve as an interface between the bacterial cell and the environment. Isolated S-layers can recrystallize into two-dimensional regular arrays in suspension or on various surfaces, thus being an appropriate material for several bionanotechnological purposes. Promising applications of S-layers include their use as biotemplates for the capture of metal ions or the synthesis of metal nanoclusters. Considering the use of S-layers as biotemplates for the organization of metal ions or metallic nanoclusters, research on potential of surface layer proteins (SLP) and metals can be understood as an interdisciplinary field, in which different biophysical techniques supply complementary information. In this review, we discuss the SLP as native or engineered “bottom-up” building blocks for metal immobilization structures. We also describe the biophysical techniques used to analyze metal binding properties as well as the information obtained from the investigation of these structures.Centro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de Ciencias Exacta