Abstract The presence of PUFA (polyunsaturated fatty acids) in cow milk, including conjugated linoleic acids (CLA) isomers, makes milk susceptible to lipid oxidation, and may lead to the formation of volatile products responsible for a rancid smell. Consequently, including natural antioxidants in the diet of dairy cattle can assist in preventing lipid oxidation. In this study, soybean oil (a source of PUFA) and different ethanolic extracts of Brazilian propolis were included in the cows' feed, and the antioxidant activity and lipid oxidation of the animals' milk was assessed. Antioxidant activity was analyzed using the DPPH method, potassium ferricyanide reduction and chelating ability. Total phenolic compounds and flavonoids were also determined. Lipid oxidation was assessed by determining conjugated dienes and the production of aldehydes (propanal, pentanal, hexanal and octanal). Increased antioxidant activity was seen in the samples of milk from cows receiving propolis. Similarly, the addition of ethanolic extract of propolis to the diet of dairy cattle increased milk protection for two treatments with propolis against lipid oxidation in terms of production of propanal and hexanal. These results confirm the positive effect of applying this natural additive to the diet of lactating cows, improving the nutritional quality of the milk produced.

Beetroot leaves (Beta vulgaris L.) are commonly cut off and discarded before using its bulb due to lack of knowledge of how to use them. Aiming at using these leaves, in the present study, in natura and dehydrated beetroot leaves were chemically characterized in terms of fatty acid composition, proximate composition, minerals, total phenolic compounds (TPC), and antioxidant activity by DPPH• in different stages (60, 80, and 100 days) of development. The beetroot leaves showed significant levels of protein and lipids in all developmental stages, and all proximate composition nutrients decreased during these maturation stages; the highest content was observed at 60 days. The Fe content decreased during the developmental stages (from 342.75 to 246.30 mg.kg-1), while the content of K increased (from 13,367.64 to 20,784.90 mg.kg-1). With regard to to fatty acid composition, linolenic acid was present in the greatest quantity, and it increase up to 2.58 mg.g-1 (in natura) and 40.11 mg.g-1 (dehydrated) at 100 days of development. The n-6/n-3 ratios were low in all stages. The TPC and antioxidant activity by DPPH• changed during the developmental stages. The TPC was highest in the 100-day dehydrated leaves (15.27±0.12 mg GAE.g-1 FW), and the 50% inhibition of DPPH• (IC50 89.52 µg.mL-1) were better in the 60-day in natura leaves. This study shows that all developmental stages produced satisfactory results, and therefore, these leaves can be reused as food. The antioxidant activity and the chemical constituents, mainly the ω-3fatty acid, increased during the stages of development.

The chemical composition and antioxidant capacity of five seeds, chia, golden flax, brown flax, white perilla, and brown perilla, were determined. The chemical properties analyzed included moisture, ash, crude protein, carbohydrates, total lipids, fatty acids, and antioxidant capacity (ABTS•+, DPPH•, and FRAP). The results showed the highest amounts of protein and total lipids in brown and white perilla. Perilla and chia showed higher amounts of alpha-linolenic fatty acid than those of flaxseed varieties, ranging between 531.44 mg g-1 of lipids in brown perilla, 539.07 mg g-1 of lipids in white perilla, and 544.85 mg g-1 of lipis in chia seed. The antioxidant capacity of the seeds, evaluated with ABTS•+, DPPH• , and FRAP methods, showed that brown perilla had greater antioxidant capacity when compared with white perilla, flax, and chia seeds.

No Brasil, nas feiras livres, mercados e distribuidores de vegetais, são cortadas e descartadas as folhas e/ou ramas destes alimentos, incluindo as folhas de cenoura (Dacus carota L.). Visando diminuir este desperdício, realizou-se o presente trabalho, que teve como objetivo caracterizar quimicamente as folhas de cenoura de cultivo orgânico em três estádios de desenvolvimento e assim indicar a melhor época para a retirada e consumo na alimentação. As folhas foram desidratadas em estufa a 70 °C por 43 horas e, em seguida, fez-se as análises de composição centesimal, atividade antioxidante, clorofila total, composição em ácidos graxos e dos minerais cálcio (Ca), sódio (Na), potássio (K), magnésio (Mg), manganês (Mn), Ferro (Fe), zinco (Zn) e cobre (Cu). Baseado nas análises realizadas foi indicado o estádio de 100 dias de desenvolvimento como o ideal para a retirada e consumo das folhas de cenoura que apresentou bons resultados de atividade antioxidante, necessitando de apenas 63,78 ± 0,5 mg.L-1 de extrato metanólico da folha para inibir 50% da concentração do radical livre DPPH (2,2-difenil-1picrilidrazil), proteína total (18,23% ± 2,8) e de ácido graxo alfa linolênico (18:3n-3/AAL) 876,55 ± 20,62 mg.100 g-1 de matéria seca.

In Brazil, street markets and vegetable distributors discard vegetable leaves and stems, including those of carrot (Dacus carota L.). Seeking to reduce the waste of vegetable parts, this study characterized chemically the leaves of organically grown carrot in three stages of development to determine the best time for their removal and consumption as food. The leaves were dehydrated in an oven at 70 °C for 43 hours and analyzed for chemical composition, antioxidant activity, chlorophyll content, fatty acid composition, and also calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu) contents. The analyses indicated 100 days of development as the ideal stage for the removal and consumption of carrot leaves with good antioxidant activity requiring only 63.78 ± 0.5 mg.L-1 methanol leaf extract to inhibit 50% of the concentration of the free radical DPPH (2,2-diphenyl-1picrilidrazil), and total protein and alpha-linolenic acid (18:3 n-3/LNA) contents of 18.23% ± 2.8 and 876.55 ± 20.62 mg.100 g-1 of dry matter, respectively.