Assessment of grazing selectivity in relation to land cover: a comparison between sheep and goats

Portugal’s Northeast production of sheep and goats are based on the exploitation of landscape by-products such as spontaneous native vegetation and agriculture leftovers. Shepherds tend the flocks throughout grazing itineraries every day, crossing a mosaic of patches of varied land uses. During the journey, the shepherd acts together with the sheep and goats to select each patch in creating an ordered sequence of land uses. The focus of the research is on the land-use composition of the grazing itineraries; determinate how they depend on the patterns of the landscape mosaic. It is utilized a data set of 26 monthly herd’s itineraries, 13 of sheep and 13 of goats, to investigate the relationship of the land uses crossed by the flocks and the land uses of the landscape, evaluating the land-use preferences and selectivity of the sheep and goats. It is utilized the divergences in the time spent and distance travelled by the herds and the area of the land uses in the landscape, the chi-square test to relate the preferred land used and the season, and the discriminate analysis to distinguish the preferences and the selectivity of the herd of sheep and the herd of goats. The herds of the sheep and the goats presented different land-use preferences over the seasons and the discriminant analysis shows that they have different landscape preferences. The herd of sheep has the highest selectivity indexes for the annual irrigated crops, the agricultural complex systems and the agroforestry land uses. The highest selectivity indexes for the herd of goats were found for the deciduous forest, the agriculture with natural and semi-natural spaces and the shrublands land uses. It was concluded that the landscape management for sheep and goats herding has to be different: the agricultural land uses are essential to the flocks of sheep and the forest land uses are decisive to the flocks of goats.

Use of inert gas-enriched atmospheres and post-packaging irradiation in shelf-life extension of watercress

Watercress (Nasturtium officinale R. Br.) is a semi-aquatic plant of the Brassicaceae family highly appreciated in the Mediterranean cuisine. It features sharp, peppery and slightly tangy taste and contains health-promoting phytochemicals. Its consumption as a fresh-cut product has increased in recent years, as well as the global market of minimally processed vegetables. This demand is driven by the growing interest in the role of food in promoting the human health and wellbeing and to meet consumer needs for fresh-like and more convenient foods. Due to the reduced shelf-life of this plant, the suitability of inert gas-enriched atmospheres and ionizing irradiation for preserving visual, nutritional and functional quality attributes during cold storage was studied. Watercress samples were gathered in the Northeast region of Portugal, rinsed in tap water and a portion was immediately analyzed (non-stored control). The remaining fresh material was packaged in polyethylene bags under N2- and Ar-enriched atmospheres, conventional atmosphere (air) and vacuum (no atmosphere). Samples under conventional atmosphere were irradiated at 1, 2 and 5 kGy of gamma-rays (predicted doses) in a 60Co experimental chamber. A non-irradiated control followed all the experiment. Then, all packaged samples were stored at 4 ºC for 7 days. The studied quality parameters included the colour that was measured with a Konica Minolta colorimeter, and total soluble solids and pH determined in squeezed juice. The proximate composition (moisture, proteins, fat, ash, carbohydrates and energy) was evaluated using the AOA C procedures. Organic acids, free sugars, fatty acids and tocopherols were analyzed by chromatographic techniques. Samples were also evaluated for its DPPH• scavenging activity, reducing power, and lipid peroxidation inhibition capacity trough the inhibition of the β-carotene bleaching and thiobarbituric acid reactive substances (TBAR S) formation. Differences among treatments were analyzed using the one-way analysis of variance (ANO VA) and a linear discriminant analysis (LDA ) was used to evaluate the effects on the overall postharvest quality. After evaluating the effect on the individual quality parameters, the LDA revealed that the Ar-enriched atmosphere and the irradiation at 2 kGy were suitable processing choices for preserving the integrity of the non-stored control samples during cold storage. Thus, these non-thermal treatments were highlighted for shelf-life extension of fresh-cut watercress.

Nitrogen vs argon: what is the most effective atmosphere for shelf-life extension of buckler sorrel leaves?

Buckler sorrel (Rumex induratus Boiss. & Reut.) is an underutilized leafy vegetable with peculiar sensory properties and potential as a gourmet food. In the food industry, different packaging methods have been used for shelf-life extension, but it is important to know how the quality of minimally processed vegetable is affected by these treatments. Recently, nitrogen and argon have been used for food packaging. Nitrogen is low soluble in water and other food constituents and does not support the growth of aerobic microbes. In turn, argon is biochemically active and appears to interfere with enzymatic oxygen receptor sites. In this study, modified atmospheres enriched with nitrogen and argon were evaluated for shelf-life extension of buckler sorrel leaves. Wild samples were gathered in Bragança, Portugal, considering local consumers’ sites and criteria. Healthy and undamaged leaves were selected, rinsed in tap water, and a portion was immediately analyzed (non-stored control). The remaining fresh material was packaged in polyethylene bags under nitrogen- and argon-enriched atmospheres and a conventional control atmosphere (air). All packaged samples were stored at 4 ºC for 12 days and then analyzed. The headspace gas composition was monitored during storage. Different quality attributes were evaluated, including visual (colour), nutritional (macronutrients, individual sugars and fatty acids) and bioactive (hydrophilic and lipophilic molecules and antioxidant properties) parameters. Different statistical tools were used; the one-way analysis of variance (ANO VA) was applied for analyse the differences among treatments and a linear discriminant analysis (LDA ) was used to evaluate the effects on the overall postharvest quality. The argon-enriched atmosphere better prevent the samples yellowing. The proximate composition did not change significantly during storage. Samples in control atmosphere revealed higher protein and ash contents and lower levels of lipids. The non-stored control samples presented the higher amounts of fructose, glucose and trehalose. The storage time increased the palmitic acid levels and decreased the content in α-linolenic and linoleic acids. The γ- e δ-tocopherols were higher after the 12 days of cold storage. Probably, the synthesis of these lipophilic compounds was a plant strategy to fight against the abiotic stress induced by storage. Higher levels of total phenolics and flavonoids and increased reducing power and β-carotene bleaching inhibition capacity were also found in the stored control samples. Once again, this result may be attributed to the intrinsic plant-protection mechanisms. Overall, the argon atmosphere was more suitable for quality preservation and shelf-life extension of buckler sorrel.

Effects of gamma and electron-beam irradiation on the individual phenolics of Viola tricolor L. edible flowers.

Edible flowers are being used in culinary preparations to improve the sensorial and nutritional qualities of food, besides improving human health due to the profusion in bioactive compounds [1]. Nevertheless, edible flowers are highly perishable and must be free of insects, which is difficult because they are usually cultivated without using pesticides [2]. Food irradiation is an economically viable technology to extend shelf life of foods, improving their hygiene and quality, while disinfesting insects [3]. The efficiency and safety of radiation processing (using Co-60 or electronaccelerators) have been approved by legal authorities (FDA, USDA, WHO, FAO), as also by the scientific community, based on extensive research [4]. Viola tricolor L. (heartseases), from Violaceae family, is one of the most popular edible flowers. Apart from being used as food, it has also been applied for its medicinal properties, mainly due to their biological activity and phenolic composition [5]. Herein, the phenolic compounds were analyzed by HPLC-DAD-ESI/MS and linear discriminant analysis (LDA) was performed to compare the results from flowers submitted to different irradiation doses and technologies (Co-60 and electron-beam). Quercetin-3-O-(6-O-rhamnosylglucoside)-7-O-rhamnoside (Figure 1) was the most abundant compound, followed by quercetin-3-O-rutinoside and acetyl-quercetin-3-O (6-O-rhamnosylglucoside)-7-O-rhamnoside. In general, irradiated samples (mostly with 1 kGy) showed the highest phenolic compounds content. The LDA outcomes indicated that differences among phenolic compounds effectively discriminate the assayed doses and technologies, defining which variables contributed mostly to that separation. This information might be useful to define which dose and/or technology optimizes the content in a specific phenolic compound. Overall, irradiation did not negatively affect the levels of phenolic compounds, providing the possibility of its application to expand the shelf life of V. tricolor and highlighting new commercial solutions for this functional food.

Cottage cheeses functionalized with fennel and chamomile extracts: comparative performance between free and microencapsulated forms

Globally, there is a trend for healthy food products, preferably incorporating natural bioactive ingredients, replacing synthetic additives. From previous screening studies, extracts of Foeniculum vulgare Mill. (fennel) and Matricaria recutita L. (chamomile) maintained nutritional properties and improved the antioxidant activity of cottage cheese. Nevertheless, this effect was limited to 7 days. Accordingly, aqueous extracts of these plants were microencapsulated in alginate and incorporated into cottage cheese to achieve an extended bioactivity. Plain cottage cheese, and cheese functionalized by direct addition of free decoctions, were prepared and compared. Independently of plant species, "functionalization type" factor did not show a significant effect on the nutritional parameters, as also confirmed in the linear discriminant analysis, where these parameters were not selected as discriminating variables. Furthermore, samples functionalized with microencapsulated extracts showed higher antioxidant activity after the 7th day, thereby demonstrating that the main purpose of this experimental work was achieved.

Basil as functional and preserving ingredient in “Serra da Estrela” cheese

Antitumor, antimicrobial and antioxidant activities of basil were studied, along with its characterization in phenolic compounds, organic acids and soluble sugars. The results placed basil as a valuable candidate for functionalization and conservation of food products, maintaining their nutritional properties, while increasing their shelf life and potential health effects. The basil leaves were then incorporated in "Serra da Estrela Cheese", either in its dehydrated form or as a decoction. The cheeses were then subject to a nutritional evaluation, being characterized for their fatty acids, minerals and CIE color parameters. To assess the combined effects of plant incorporation and storage time, a 2-way ANOVA was used to process the results, further analysed through a linear discriminant analysis. Overall, basil leaves provided antioxidant activity to the cheeses, reduced the moisture, and preserved the unsaturated fatty acids and proteins. Comparing both incorporation types, the decoctions had a higher functionalizing and conservative effect.