The search for new food products that promote consumers health has always been of great interest. The dairy industry is perhaps the best example regarding the emergence of new products with claimed health benefits. Cheese whey (CW), the by-product resulting from cheese production, and second cheese whey (SCW), which is the by-product of whey cheese manufacture, have proven to contain potential ingredients for the development of food products with improved nutritional characteristics and other functionalities. Nowadays, due to their nutritional quality, whey products have gained a prominent position among healthy food products. However, for a long time, CW and SCW were usually treated as waste or as animal feed. Due to their high organic content, these by-products can cause serious environmental problems if discarded without appropriate treatment. Small and medium size dairy companies do not have the equipment and structure to process whey and second cheese whey. In these cases, generally, they are used for animal feed or discarded without an appropriate treatment, being the cause of several constraints. There are several studies regarding CW valorization and there is a wide range of whey products in the market. However, in the case of SCW, there remains a lack of studies regarding its nutritional and functional properties, as well as ways to reuse this by-product in order to create economic value and reduce environmental impacts associated to its disposal.

BACKGROUND: In Southern European countries, whey cheeses are normally produced with ovine or caprine whey. Cow's cheese whey can also be used, although the whey cheese yield is low (2-3%, w/v) which discourages its use. In the present study, bovine cheese whey was concentrated by ultrafiltration for the production of four types of whey cheeses (Requeijão): conventional, without any addition (WC); with 10% (w/w) addition of cream (WCC); with cream fermented with Kefir culture (WCCK); and with cream fermented with Bifidobacterium sp. culture (WCCBB12). RESULTS: Whey cheeses with cream presented lower protein content (330-360 g kg −1 , dry basis) and higher levels of total solids (220-250 g kg −1) and fat (300-330 g kg −1 , dry basis) than WC. C16:0 and C18:1 were the most abundant fatty acids present, with 31% and 38%, respectively. The small differences found concerning instrumental determination of colour and texture were not perceived by panelists. However, the presence of Kefir and probiotics decreased the elastic modulus (G') of the samples, as well as their viscosity. Fermentation with Kefir presented the highest counts of lactic acid bacteria (7 logUFC g −1). However, after 14 days of refrigerated storage, the counts of yeasts and moulds reached 6 logUFC g −1 in all products, indicating the need for appropriate packaging solutions. CONCLUSION: Ultrafiltration of bovine whey allows for the efficient production of bovine whey cheeses. The addition of cream fermented with Kefir or BB12 appears to be an efficient methodology to incorporate Kefir or probiotic bacteria in Requeijão, improving its nutritional and sensory characteristics, alongside the potential for the extension of its shelf-life.

In the following study, three different dairy by-products, previously concentrated by ultrafiltration (UF), were used as ingredients in the production of reduced-fat (RF) washed curd cheeses in order to improve their characteristics. Conventional full-fat (FF) cheeses (45% fat, dry basis (db)) and RF cheeses (20–30% fat, db) were compared to RF cheeses produced with the incorporation of 5% concentrated whey (RF + CW), buttermilk (RF + CB) or sheep second cheese whey (RF + CS). Protein-to-fat ratios were lower than 1 in the FF cheeses, while RF cheeses ranged from 1.8 to 2.8. The tested by-products performed differently when added to the milk used for cheese production. The FF cheese showed a more pronounced yellow colour after 60 and 90 days of ripening, indicating that fat plays an important role regarding this parameter. As far as the texture parameters are concerned, after 60 days of ripening, RF cheeses with buttermilk presented similar results to FF cheeses for hardness (5.0–7.5 N) and chewiness (ca. 400). These were lower than the ones recorded for RF cheeses with added UF concentrated whey (RF + CW) and second cheese whey (RF + CS), which presented lower adhesiveness values. RF cheeses with 5% incorporation of buttermilk concentrated by UF presented the best results concerning both texture and sensory evaluation.

The objective of this work was the use of goat and sheep liquid whey concentrates (LWCs) produced by ultrafiltration (UF) for the manufacturing of frozen yoghurts. In a first step, natural yoghurts using only goat’s and sheep’s LWCs as raw material were obtained. One day after production, these yoghurts were used to produce frozen yoghurts with different concentrations of added inulin. The physicochemical characteristics of ewe’s and goat’s yoghurts were significantly different regarding dry matter, protein, fat and minerals. Ewe’s yoghurts were solid, while goat’s yoghurts behaved as a viscous liquid. Frozen yoghurts with different levels of inulin addition also presented significant differences concerning physicochemical and microbiological characteristics. Overrun was similar for all formulations except for that produced with ewe’s LWC containing 5.0% inulin, which presented a significantly higher value. Higher meltdown rates in goat’s frozen yoghurts were observed. The survival rates of lactic acid bacteria were lower than the data reported for similar products. Concerning sensory acceptance, both products showed encouraging results. It can be considered that the production of frozen yoghurts by using LWCs as the main ingredient can be an interesting option to broaden the product portfolio of small/medium scale dairy producers.

Nuclear magnetic resonance (NMR) spectroscopy has been extensively used to date for the analysis of olive oil samples and constitutes a valuable tool particularly for the study of the triacylglycerol fraction, which is the major fraction of olive oils. In this report, we demonstrate the usefulness of one-dimensional NMR spectroscopy (1 H and 13 C NMR) for the nondestructive analysis of the triacylglycerol fraction of olive oils. To achieve this goal, 13 C spectral editing technique known as distortionless enhancement by polarization transfer (DEPT), namely 13 C NMR DEPT 45, 13 C NMR DEPT 90, 13 C NMR DEPT 135 was used for the analysis of the triacylglycerol fraction of the olive oil sample owing to the simplification on peak assignments of 13 C spectra. The suitability and usefulness of those DEPT experiments using different angle values in only one pulse sequence will be explored on the interpretation of 13 C NMR spectra. In overall, DEPT tool improves the sensitivity of the analysis due to the enhancement in the signal-to-noise ratio, which is important for this type of analysis contributing to the characterization of olive oils.