Edible films are thin preformed layers that provide food protection against adverse environmental conditions. Despite milk proteins being functional ingredients that can provide interesting features to films, there is scarce information evaluating their influence on film properties and stability. For this reason, this research work compared the mechanical (thickness, tensile strength, elongation at break), hydrodynamic (moisture content, water solubility, swelling ratio, water vapor transmission rate), color and antioxidant (DPPH) properties of edible films based on casein and whey protein isolate (two types, WPI1 and WPI2). Films with casein displayed the highest thickness (0.193 mm), elongation at break (49.67%), moisture content (40.21%) and antioxidant capacity (32.64% of DPPH inhibition), while obtaining the lowest water vapor transmission rate (15.28 g/m2·day). Significant differences were found in the color properties, mainly between films with casein and those made with WPI. Films containing WPI1 and WPI2 were statistically similar in thickness, tensile strength and color properties. The results showed that the properties of the edible films depended on the type of milk protein used. Thus, it is important to evaluate the features provided by different ingredients and formulations for obtaining edible films that properly preserve food.

Raspberry production represents an alternative for farmers in the temperate zones of Mexico. Due to the environmental impact caused by conventional agriculture, there is currently greater demand for organic food in the national and international market. To achieve this need, new fertilization techniques based on organic amendments are being tested. In the present study, yields and quality were evaluated over a 3-year period (2015, 2016 and 2017) as well as the phytochemical compounds of the production in 2017, with management of organic versus conventional fertilization of raspberry crop in open field in Cuauhtémoc, Chihuahua, Mexico. During the three years of study, the conventional fertilization system obtained higher yields, compared to the organic one, with values of 2,698 and 2,351 g per linear meter in 2015, 2,423 and 1,301 g per linear meter in 2016 and the data for 2017 were 3,077 and 2,550 g per linear meter, respectively. Regarding quality, the results showed no statistical differences between the two systems of production about colour, firmness, total soluble solids, titratable acidity and pH of the fruit. Differently the composition of phytochemicals, phenols, flavonoids, total anthocyanins and antioxidant capacity was better under the organic management. In conclusion, the conventional system showed higher yields, the quality of the fruits was not different between the two systems, while the levels of phytochemicals were higher with the organic farming. Therefore, it is important to continue the research in order to improve soil fertility and achieve higher yields under the organic management.

Raspberries are important sources of bioactive compounds, whose synthesis is influenced by the fertilization system and the maturity stage. This study evaluated the effect of organic and conventional fertilization systems on raspberries at three maturity stages, pink, ripe, and overripe. Physicochemical characteristics, bioactive compounds (phenolic profile, vitamin C), antioxidant capacity (DPPH, FRAP, TEAC, and ORAC), phenolic-associated enzyme, phenylalanine ammonia lyase (PAL), and antioxidant enzymes (SOD, CAT, GPx, and APX) were evaluated. The physicochemical determination of the fruit did not reveal differences between fertilization systems. Regarding bioactive compounds, higher content of anthocyanins was found in organic raspberries at all maturity stages. Organic fertilization increased the content of ellagic acid and gallic acid at all stages of maturity. Higher content of caffeic, hydroxybenzoic, protocatechuic acid, and vitamin C was observed in organic raspberry at the overripe stage. Raspberries grown with organic fertilization exhibited higher values of antioxidant capacity by the DPPH, FRAP, and TEAC methods at all maturity stages. Raspberries under organic fertilization showed significantly greater activity of CAT, SOD, APX, GPX, and PAL. The present study suggests that organic fertilization induces oxidative stress causing an increase in antioxidant defense mechanisms, enhancing bioactive compound production, and improving antioxidant capacity in raspberries.

Raspberries are widely consumed; the taste of the fruit is determined by the interaction between sugars, organic acids and a set of volatile compounds. Meanwhile, organic agriculture has developed rapidly as an alternative to conventional system and has been driven by the demand for pesticide-free food that brings greater benefits to human health. However, this system can alter the integral quality of the fruit, including the aroma, which has been little studied. Therefore, the objective of this study was to evaluate the effect of the application of organic and conventional fertilizers, in the presence of volatile compounds synthesized in the cv. ‘Heritage’ raspberry, during two crop cycles. The qualitative profile of volatile compounds was analysed by mass gas chromatography, obtaining as a result that fertilization treatments significantly affected the emission of volatile compounds in the most abundant functional group (C13 norisoprenoids) 48.5 vs. 25.8% and 56.9 vs. 29.1% in conventional and organic, in 2017 and 2018, respectively (p ≤ 0.05). The crop cycle affected the concentration of aldehydes (11.2 vs. 30.6% in organic, in 2017 and 2018, respectively (p ≤ 0.05). Impact compounds such as α-ionone (13.92 vs. 9.08% and 25.34 vs. 9.17% in conventional and organic in 2017 and 2018, respectively) and β-ionone (24.93 vs. 14.10% and 22.66 vs. 15.94% in conventional and organic in 2017 and 2018, respectively), presented greater abundance in conventional fertilization (p ≤ 0.05). Since there were changes in the volatile compounds, it is recommended to study whether the consumer perceives these changes.

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