Yolanda Aguilera

Characterization of Industrial Onion Wastes (Allium cepa L.): Dietary Fibre and Bioactive Compounds

The food industry produces a large amount of onion wastes, making it necessary to search for possible ways for their utilization. One way could be to use these onion wastes as a natural source of high-value functional ingredients, since onion are rich in several groups of compounds, which have perceived benefits to human health. The objective of this work is to gain knowledge of any differences between the different onion wastes obtained from industry and non-commercial bulbs to use them as food ingredients rich in specific compounds. The results showed that brown skin and top–bottom could be potentially used as functional ingredient rich in dietary fibre, mainly in insoluble fraction, and in total phenolics and flavonoids, with high antioxidant activity. Moreover, brown skin showed a high concentration of quercetin aglycone and calcium, and top–bottom showed high concentration of minerals. Outer scales could be used as source of flavonols, with good antioxidant activity and content of dietary fibre. However, inner scales could be an interesting source of fructans and alk(en)yl cystein sulphoxides. In addition, discarded onions (cvs Recas and Figueres) could be used as a good source of dietary fibre, and cv Recas also as a source of phenolics compounds.

Starch, Functional Properties, and Microstructural Characteristics in Chickpea and Lentil As Affected by Thermal Processing

Changes in starch, functional, and microstructural characteristics that occurred in chickpea and lentil under soaking, cooking, and industrial dehydration processing were evaluated. Available starch in raw legumes represented 57-64%, and resistant starch (RS) is a significant component. As a result of cooking, available starch contents of soaked chickpea and lentil were significantly increased (21 and 12%, respectively) and RS decreased (65 and 49%, respectively) compared to raw flours. A similar trend was exhibited by dehydration, being more relevant in lentil (73% of RS decrease). The minimum nitrogen solubility of raw flours was at pH 3, and a high degree of protein insolubilization (80%) was observed in dehydrated flours. The raw legume flours exhibited low oil-holding capacities, 0.95-1.10 mL/g, and did not show any change by thermal processing, whereas water-holding capacities rose to 4.80-4.90 mL/g of sample. Emulsifying activity and foam capacity exhibited reductions as a result of cooking and industrial dehydration processing. The microstructural observations were consistent with the chemical results. Thus, the obtained cooked and dehydrated legume flours could be considered as functional ingredients for food formulation.

Phenolic Profile and Antioxidant Capacity of Chickpeas (Cicer arietinum L.) as Affected by a Dehydration Process

This study presents the effects of soaking, cooking and industrial dehydration on the phenolic profile, and antioxidant capacity in two chickpea varieties (Sinaloa and Castellano). Chromatographic analysis identified a total of 24 phenolic components, being isoflavones the main phenolics in raw and processed Sinaloa and Castellano flours. The impact of the industrial dehydration was different depending on the chickpea variety. Although Castellano chickpea exhibited the highest levels of phenolic compounds (103.1xa0μg/g), significant reductions were observed during processing; in contrast, the dehydration did not cause any further effects in Sinaloa flours. Interestingly, Sinaloa variety showed high thermal stability of isoflavones during processing. As expected, the levels of antioxidant capacity were in accordance with the behavior of phenolic compounds exhibiting noticeable reductions in Castellano chickpea and not relevant changes in Sinaloa chickpea. Thus, the significant occurrence of bioactive phenolic compounds along with the relevant antioxidant capacities of dehydrated chickpea flours make them to be considered functional ingredients for their beneficial health effects, especially in case of Sinaloa.

Evaluation of Phenolic Profile and Antioxidant Properties of Pardina Lentil As Affected by Industrial Dehydration

This study presents the effects of soaking, cooking, and industrial dehydration treatments on phenolic profile and also on antioxidant properties in Pardina lentil. HPLC-PAC and HPLC-MS (ESI) analysis identified a total of 35 phenolic compounds in raw and processed lentil flours, corresponding to catechins and procyanidins (69% of the total of identified phenolic compounds), flavonols (17%), flavones, and flavanones (5%), and hydroxybenzoic and hydroxycinnamic compounds (5 and 4%, respectively). During the industrial process, catechins and procyanidins, flavonols, flavones, and flavanones decreased, while hydroxybenzoic compounds exhibited an important increase. In addition, raw lentils showed high values of the antioxidant activity (66.97 μmol Trolox/g); although the thermal processing promotes decreased, the levels of antioxidant activity were still relevant. Thus, the significant occurrence of bioactive phenolic compounds along with the interesting antioxidant capacity of dehydrated lentil flours make them useful for daily inclusion in the human diet as ready-to-use for special meals to specific populations.

Changes in nonnutritional factors and antioxidant activity during germination of nonconventional legumes

The present study describes the effects of germination on nonnutritional factors and antioxidant activity in the nonconventional legumes Vigna unguiculata (cowpea), Canavalia ensiformis (jack bean), Lablab purpureus (dolichos), and Stizolobium niveum (mucuna). Protease inhibitors and lectins were detected in raw legumes and were significantly decreased during the germination. Regarding total and individual inositol phosphates (IP5-IP3), important reductions of IP6 and high increases in the rest of inositol phosphates were also detected during this process. In addition, total phenols, catechins, and proanthocyanidins increased, accompanied by an overall rise of antioxidant activity (79.6 μmol of Trolox/g of DW in the case of mucuna). Germination has been shown to be a very effective process to reduce nonnutritional factors and increase bioactive phenolic compounds and antioxidant activities of these nonconventional legumes. For this reason, they could be used as ingredients to obtain high-value legume flours for food formulation.

Effect of sterilisation on dietary fibre and physicochemical properties of onion by-products

Food industries are forced to develop productions without secondary residues. Therefore, there is a considerable emphasis on the recovery, recycling and upgrading of wastes. The possibility has been suggested for the conversion of onion waste into food ingredients, but with a stabilisation treatment being necessary. The objective of this work was to study the effect of sterilisation on fibre fractions, fibre composition and physicochemical properties of onion by-products to evaluate the use of sterilised onion by-products as a source of fibre. Sterilisation produced insoluble dietary fibre decreases and soluble dietary fibre increases, improving the soluble:insoluble ratio. Uronic acids of insoluble dietary fibre were partly solubilised and losses of cellulose and Klason lignin were observed. Physicochemical properties slightly changed with sterilisation. Sterilised by-products showed less oil holding capacity, cation exchange capacity and swelling capacity than control ones, although their physicochemical properties were generally higher than those of cellulose. Therefore, sterilisation would be considered a good method to stabilise onion by-products to use as a potential dietary fibre ingredient.

Phenolic compounds in fruits and beverages consumed as part of the mediterranean diet: their role in prevention of chronic diseases

The objective of this review was to assess, based on human data, the role of phenolic compounds in selected plant foods consumed as part of the Mediterranean diet in the prevention of chronic diseases (CDs) like cardiovascular disease, cancer and neurodegenerative conditions. Fruits and vegetables are rich sources of phenolic compounds and based on scientific data it would be expected that their consumption, as part of the diet, would be responsible for their documented preventive role of chronic diseases. The results of the review of scientific literature on human clinical trials revealed that in some studies polyphenols exert a positive effect in the prevention of cardiovascular disease, essentially blood pressure and arterial dilation, certain types of cancer and neurodegenerative disorders. However, such effects are not consistent with other clinical studies in which no effect has been found. Therefore, the level of evidence for a beneficial effect in humans of phenols on the prevention of CDs is weak and need to be strengthened by additional studies addressing potential confounding factors, such as interaction of phenols with other bioactive substances in foods and potential pro-oxidant effects.

Estimation of scavenging capacity of melatonin and other antioxidants: Contribution and evaluation in germinated seeds

Seven edible seeds for the levels of melatonin, phenolic compounds and their antioxidant capacity were evaluated during germination process. Radical scavenging parameters were also studied in standard antioxidants to understand their antiradical actions. Germination brought about significant increases of total phenol compounds in all edible seeds, showing red cabbage, radish and broccoli the highest contents (21.6, 20.4 and 16.4 mg GAE/g DW, respectively). The concentration of melatonin is greatly variable in edible seeds, exhibiting significant increases during germination. The highest levels were found in red cabbage (857 pg/g DW) radish (536 pg/g DW) and broccoli (439 pg/g DW). The germinated seeds which had the highest levels of polyphenols and melatonin were those that showed the most relevant antiradical activities (>97%). This information is valuable for the incorporation of red cabbage, radish and broccoli germinated seeds into the diet to promote potential health benefits.

Fetal undernutrition is associated with perinatal sex-dependent alterations in oxidative status.

Intrauterine growth retardation predisposes to hypertension development, known as fetal programming. Females are less susceptible, which has been mainly attributed to estrogen influence. We hypothesize that perinatal differences in oxidative status might also contribute. We studied 21-day-old (prepuberal) and 6-month-old male and female offspring from rats fed ad libitum during gestation (Control) or with 50% of Control daily intake from day 10 to delivery (maternal undernutrition, MUN). We assessed in vivo blood pressure and the following plasma biomarkers of oxidative status: protein carbonyls, thiols, reduced glutathione (GSH), total antioxidant capacity, superoxide anion scavenging activity (SOSA) and catalase activities; we calculated a global score (oxy-score) from them. Estradiol and melatonin concentration was measured in young rats. Prepuberal MUN males were normotensive but already exhibited increased carbonyls and lower thiols, GSH, SOSA and melatonin; oxy-score was significantly lower compared to Control males. Prepuberal MUN females only exhibited reduced SOSA compared to Control females. Adult rats from all experimental groups showed a significant increase in carbonyls and a decrease in antioxidants compared to prepuberal rats; oxy-score was negative in adult rats suggesting the development of a prooxidative status as rat age. Adult MUN males were hypertensive and exhibited the highest increase in carbonyls despite similar or even higher antioxidant levels compared to Controls. Adult MUN females remained normotensive and did not exhibit differences in any of the biomarkers compared to Controls. The better global antioxidant status developed by MUN females during perinatal life could contribute to their protection against hypertension programming.

Effect of Illumination on the Content of Melatonin, Phenolic Compounds, and Antioxidant Activity During Germination of Lentils (Lens culinaris L.) and Kidney Beans (Phaseolus vulgaris L.)

This study reports the effects of two different illumination conditions during germination (12 h light/12 h dark vs 24 h dark) in lentils (Lens culinaris L.) and kidney beans (Phaseolus vulgaris L.) on the content of melatonin and phenolic compounds, as well as the antioxidant activity. Germination led to relative increase in melatonin content and significant antioxidant activity, while the content of phenolic compounds decreased. The highest melatonin content was obtained after 6 days of germination under 24 h dark for both legumes. These germinated legume seeds with improved levels of melatonin might play a protective role against free radicals. Thus, considering the potent antioxidant activity of melatonin, these sprouts can be consumed as direct foods and be offered as preventive food strategies in combating chronic diseases through the diet.