Impacto del uso de tecnologías no térmicas sobre distintos parámetros nutricionales y de calidad en alimentos líquidos / Non-thermal technologies impact on nutritional and quality parameters in liquid foods

In the last decade have appeared in the Spanish market new products based on mixtures of fruit juices and milk as well as beverages mixtures of fruit and/or vegetables, which have a good acceptance by consumers and with a high nutritional value largely due to its high content in bioactive compounds as well as antioxidant capacity. Traditionally, liquid food such as fruit and/or vegetables juices, as well as milk, have been preserved by thermal treatment such as pasteurization and sterilization. However these processes can cause loss of compounds responsible for the organoleptic and nutritional quality of food. Currently there is a growing demand by the consumer for minimally processed food and which in turn are safe from the microbiological point of view, a fact that is driving the development of new conservation methods. Nonthermal processes such as high hydrostatic pressure, pulsed electric fields and ultrasound, which can be used with this goal without affecting the quality of food. Although the effectiveness of these treatments is known for safe food, is now when is possible to produce the greater technological advances for it to marketing. In the present doctoral thesis, the main objective is to establish the conditions of nonthermal processing to obtain beverages with a high content in bioactive compounds as well as antioxidant capacity. In addition it is important to compare the effects of these treatments on the organoleptic and nutritional characteristics, with those occurring after the implementation of a traditional heat treatment. Subsequently, also it was studied the degree of permeability of the cell membranes of blueberries using the extent of the impedance, to optimize the parameters of processing and use thermal and nonthermal processing in the extraction of bioactive compounds with antioxidant capacity.En la última década han aparecido en el mercado español nuevos productos basados en mezclas de zumos de frutas y leche así como bebidas mezclas de vegetales, que presentan una buena aceptación por parte del consumidor y con un gran valor nutricional, debido en gran parte a su alto contenido en compuestos bioactivos así como capacidad antioxidante. Tradicionalmente los alimentos líquidos como zumos de fruta y/o vegetales, así como la leche, han sido conservados mediante técnicas por calor como la esterilización. Sin embargo estos procesos pueden provocar una pérdida de compuestos responsables de la calidad organoléptica y nutricional de los alimentos. Actualmente existe una demanda creciente por parte del consumidor de alimentos mínimamente procesados y que a la vez sean seguros desde el punto de vista microbiológico, hecho que está impulsando el desarrollo de nuevos métodos de conservación. Procesos no térmicos como las altas presiones hidrostáticas, pulsos eléctricos de alta intensidad y ultrasonidos, pueden utilizarse con este objetivo sin que se vea afectada la calidad de los alimentos. Aunque la eficacia de estos tratamientos se conoce para obtener alimentos seguros, es ahora cuando se están produciendo los mayores avances tecnológicos para hacer posible su comercialización. En la presente tesis doctoral, el objetivo principal es establecer las condiciones de procesado no térmico para obtener bebidas con un alto contenido en compuestos bioactivos así como capacidad antioxidante. Además se comparan los efectos de estos tratamientos sobre las características nutricionales y organolépticas con los que se producen tras la aplicación de un tratamiento térmico tradicional. Posteriormente, se estudia el grado de permeabilidad de las membranas celulares de arándanos utilizando la medida de la impedancia, para optimizar los parámetros del procesamiento y poder utilizar los tratamientos térmicos y no térmicos en la extracción de compuestos bioactivos con capacidad antioxidante

Electronic sensor technologies in monitoring quality of tea: A review

Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms (ESPs), in terms of an electronic nose (e-nose), electronic tongue (e-tongue), and electronic eye (e-eye) equipped with progressive data processing algorithms, not only can accurately accelerate the consumer-based sensory quality assessment of tea, but also can define new standards for this bioactive product, to meet worldwide market demand. Using the complex data sets from electronic signals integrated with multivariate statistics can, thus, contribute to quality prediction and discrimination. The latest achievements and available solutions, to solve future problems and for easy and accurate real-time analysis of the sensory-chemical properties of tea and its products, are reviewed using bio-mimicking ESPs. These advanced sensing technologies, which measure the aroma, taste, and color profiles and input the data into mathematical classification algorithms, can discriminate different teas based on their price, geographical origins, harvest, fermentation, storage times, quality grades, and adulteration ratio. Although voltammetric and fluorescent sensor arrays are emerging for designing e-tongue systems, potentiometric electrodes are more often employed to monitor the taste profiles of tea. The use of a feature-level fusion strategy can significantly improve the efficiency and accuracy of prediction models, accompanied by the pattern recognition associations between the sensory properties and biochemical profiles of tea

Pulsed electric field (PEF) recovery of biomolecules from Chlorella : Extract efficiency, nutrient relative value, and algae morphology analysis

This study investigated the effects of pulsed electric field (PEF) (3 kV/cm, 44 pulses, 99 kJ/kg), solvent (H2O or 50 % DMSO) and time (0, 10, 20, 30, 60, 90, 120 and 180 min) on the extraction of Chlorella antioxidant biomolecules and minerals. The results showed that PEF treatment increased the biomolecules recovery. For the extraction time of 120 min, more proteins and polyphenols were obtained using water, while more chlorophyll a and b, and carotenoids were obtained using 50 % DMSO as the extraction solvent. The extracts mineral concentration (PEF vs control) were analysed including Mg, P, Ca, Fe and Zn, and the Relative Nutrient Values results indicated that Chlorella H2O-extracts could be used as a mineral source for different populations. Finally, the fluorescence and scanning electron microscopy revealed the electroporation effect of PEF

Water-soluble polysaccharides from Opuntia stricta Haw. fruit peels: Recovery, identification and evaluation of their antioxidant activities

Opuntia stricta Haw. is considered as one of the most common cactus plant growing in Tunisia. Extracting valuable compounds from its fruit peel, considered as by-product, is drawing more and more attention, making it on the verge of commercialization. Water-soluble polysaccharides were extracted from Opuntia stricta Haw. peels, and their chemical composition assessed using thin layer chromatography. The antioxidant activities of the extracted polysaccharides were assessed using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, total antioxidant activity and reducing power capacity. The extraction yield of water-soluble polysaccharides was 7.53±0.86%. The chemical composition revealed the presence of rhamnose, arabinose, glucose, mannose, galactose and galacturonic acid. The infra-red spectroscopic analysis showed a similar structure to that of Opuntia ficus-indica polysaccharide peels. Additionally, the extracted polysaccharides exhibited high antioxidant activities. In fact, the free radical scavenging activity (half inhibition concentration = 6.5 mg ml-1 with 94.9% inhibition at 50 mg ml-1), the total antioxidant activity (100 μg ascorbic acid equivalent at 50 mg polysaccharides) and the reducing power capacity (absorbance 700 nm = 0.7 at 50 mg ml-1), appeared to be interesting compared to natural and synthetic antioxidants. Therefore, water-soluble polysaccharides from Opuntia stricta Haw. fruit peels could be a natural alternative to replace synthetic antioxidants

Evaluation of Pulsed Electric Field-Assisted Extraction on the Microstructure and Recovery of Nutrients and Bioactive Compounds from Mushroom (Agaricus bisporus)

Pulsed electric field (PEF) is a sustainable innovative technology that allows for the recovery of nutrients and bioactive compounds from vegetable matrices. A. bisporus was chosen for its nutritional value and the effect of PEF pretreatment was evaluated using different conditions of electric field (2-3 kV/cm), specific energy (50-200 kJ/kg) and extraction time (0-6 h) to obtain the best conditions for nutrient and bioactive compound extraction. Spectrophotometric methods were used to evaluate the different compounds, along with an analysis of mineral content by inductively coupled plasma mass spectrometry (ICP-MS) and the surface was evaluated using scanning electron microscopy (SEM). In addition, the results were compared with those obtained by conventional extraction (under constant shaking without PEF pretreatment). After evaluating the extractions, the best extraction conditions were 2.5 kV/cm, 50 kJ/kg and 6 h which showed that PEF extraction increased the recovery of total phenolic compounds in 96.86%, carbohydrates in 105.28%, proteins in 11.29%, and minerals such as P, Mg, Fe and Se. These results indicate that PEF pretreatment is a promising sustainable technology to improve the extraction of compounds and minerals from mushrooms showing microporation on the surface, positioning them as a source of compounds of great nutritional interest

Citrus aurantium l. Active constituents, biological effects and extraction methods. an updated review

Citrus genus is a prominent staple crop globally. Long-term breeding and much hybridization engendered a myriad of species, each characterized by a specific metabolism generating different secondary metabolites. Citrus aurantium L., commonly recognized as sour or bitter orange, can exceptionally be distinguished from other Citrus species by unique characteristics. It is a fruit with distinctive flavor, rich in nutrients and phytochemicals which possess different health benefits. This paper presents an overview of the most recent studies done on the matter. It intends to provide an in-depth understanding of the biological activities and medicinal uses of active constituents existing in C. aurantium. Every plant part is first discussed separately with regards to its content in active constituents. All extraction methods, their concepts and yields, used to recover these valuable molecules from their original plant matrix are thoroughly reported

Improvement of the probiotic growth-stimulating capacity of microalgae extracts by pulsed electric fields treatment

This study aimed to investigate the nutritional character (carbohydrates, proteins, pigments, and phycocyanin), total antioxidant capacity (TAC) and the capability of simulating the growth of Lactobacillus rhamnosus of different extracts from C. vulgaris and A. platensis by means of the application of conventional aqueous extraction procedure and pulsed electric field (PEF) extraction technology. It was confirmed a significantly improved nutritional profile of Chlorella and Spirulina extracts obtained by PEF technology pre-treatment (3 kV/cm, 100 kJ/kg), with specifically higher values in total carbohydrate, Chlorophyll a, Chlorophyll b, and carotenoids content, and TAC. Additionally, Spirulina PEF extract showed a probiotic's growth-stimulating capability of 1 log10 cycle when fermented by Lactobacillus rhamnosus, with a metabolomic profile specifically rich in bioactive short chain fatty acids (SCFAs) and organic acids (3-phenyl lactic acid). The present study points out the applicability of PEF extraction technology under optimized conditions to improve the nutritional and functional character of microalgae and cyanobacterial-derived ingredients

Influence of Geographical Location of Spirulina (Arthrospira platensis) on the Recovery of Bioactive Compounds Assisted by Pulsed Electric Fields

Spirulina (Arthrospira platensis) has been consumed by humans since ancient times. It is rich in high added-value compounds such as chlorophylls, carotenoids and polyphenols. Pulsed electric fields (PEF) is an innovative non-thermal technique that improves the extraction of bioactive compounds from diverse sources. PEF pre-treatment (3 kV/cm, 100 kJ/kg) combined with supplementary extraction with binary solvents at different times was evaluated to obtain the optimal conditions for extraction. In addition, the results obtained were compared with conventional treatment (without PEF pre-treatment and constant shaking) and different strains of Spirulina from diverse geographical locations. The optimal extraction conditions for recovering the bioactive compounds were obtained after applying PEF treatment combined with the binary mixture EtOH/H2O for 180 min. The recovery of total phenolic content (TPC) (19.76 ± 0.50 mg/g DM (dry matter) and carotenoids (0.50 ± 0.01 mg/g DM) was more efficient in the Spirulina from Spain. On the other hand, there was a higher recovery of chlorophylls in the Spirulina from China. The highest extraction of total antioxidant compounds was in Spirulina from Costa Rica. These results show that PEF, solvents and the condition of growing affect the extraction of antioxidant bioactive compounds from Spirulina. The combination of PEF and EtOH/H2O is a promising technology due to its environmental sustainability

Application of ultrasound as clean technology for extraction of specialized metabolites from stinging nettle (Urtica dioica L.)

Nettle is a highly valued medicinal plant that is still largely neglected, both in terms of nutrition and use for pharmacological purposes. Tinctures, i.e., alcoholic extracts, are becoming increasingly popular nettle products, mainly because they allow better availability of phytochemicals and their stability over a longer period of time. The production of alcoholic extracts is a chemically demanding process that is still usually carried out using conventional techniques, which have numerous drawbacks. The use of green technologies such as ultrasound-assisted extraction (UAE), which is characterized by high efficiency of phytochemical extraction, shorter treatment time, and a much lower environmental footprint, is a suitable and sustainable solution. Therefore, the aim of this study is to determine the influence of the extraction method, conventional and ultrasound (by varying two ultrasound equipment systems), time and ethanol concentration on the extraction of specialized metabolites from nettle powder. Ultrasonic extraction using a probe system significantly contributed to increase the ascorbic acid yield, polyphenolic compounds, and antioxidant capacity of nettle extracts compared to conventional extraction. In addition, when a probe system was used during UAE, significantly less time was required for isolation of individual specialized metabolites compared to ultrasonic extraction in the bath. Ethanol concentration (50 and 80% v/v) also proved to be an important factor in the efficiency of extraction of specialized metabolites, with 80% ethanol being more effective for the isolation of ascorbic acid and pigment compounds (chlorophyll and carotenoids), while 50% v/v for the extraction of polyphenolic compounds. It can be concluded that extraction with the ultrasonic probe system is much more efficient in obtaining higher yields of specialized metabolites from nettle powder in a shorter time (average process duration 5-10 min) both compared to UAE in the bath and classical extraction. However, optimization of the key factors of time, solvent type, and ultrasonic power is necessary to maintain the nutritional quality of the nettle extract in order to obtain a final product with a high specialized metabolites content, antioxidant capacity, and functional value. The future application of alcoholic nettle extracts is based on the fact that these products have significant potential as functional foods and pharmacological preparations for the treatment of a number of but also to strengthen the immune system, mainly due to the rich nutritional composition and high content of various specialized metabolites. The prepared extracts can be safely taken orally by diluting the tinctures with water immediately before ingestion

Application of Pinhole Plasma Jet Activated Water against Escherichia coli, Colletotrichum gloeosporioides, and Decontamination of Pesticide Residues on Chili (Capsicum annuum L.)

Plasma activated water (PAW) generated from pinhole plasma jet using gas mixtures of argon (Ar) and 2% oxygen (O2) was evaluated for pesticide degradation and microorganism decontamination (i.e., Escherichia coli and Colletotrichum gloeosporioides) in chili (Capsicum annuum L.). A flow rate of 10 L/min produced the highest concentration of hydrogen peroxide (H2O2) at 369 mg/L. Results showed that PAW treatment for 30 min and 60 min effectively degrades carbendazim and chlorpyrifos by about 57% and 54% in solution, respectively. In chili, carbendazim and chlorpyrifos were also decreased, to a major extent, by 80% and 65% after PAW treatment for 30 min and 60 min, respectively. E. coli populations were reduced by 1.18 Log CFU/mL and 2.8 Log CFU/g with PAW treatment for 60 min in suspension and chili, respectively. Moreover, 100% of inhibition of fungal spore germination was achieved with PAW treatment. Additionally, PAW treatment demonstrated significantly higher efficiency (p < 0.05) in controlling Anthracnose in chili by about 83% compared to other treatments