Dry cured hams were investigated for their ability to develop red color even at low temperature (3–4 °C) and in the absence of added nitrites; results were compared with those obtained from nitrite-free hams made at conventional warm maturing temperatures. Colorimetric parameters (L*, a*, b*, and hue) and concentration of the main pigments Zn protoporphyrin IX (ZnPP) and heme were measured at three stages of preparation (six, nine, and 12 months), showing that red color was successfully formed at low temperatures, though at a slower rate and less intensively than under warm conditions. Major differences in the pattern of color development were found with the two processing temperatures. While the typical features of an enzyme-dependent mechanism, with a progressive drop in enzyme activity paralleling the synthesis of Zn protoporphyrin IX, were observed at warm temperatures, the same did not occur in cold-made hams, where the enzyme activity was almost unchanged throughout the process. These results, along with data from a descriptive sensory analysis, are supportive of a non-enzymatic mechanism leading to ZnPP (hence the red color) under cold conditions, with an estimated three-month delay compared with nitrite-free hams manufactured in a warm maturing regimen.

The 87Sr/86Sr ratio of horticultural products mostly derives from that of the bioavailable Sr fraction of the soil where they grow and, therefore, varies according to the local geolithological features. This study investigated the intra- and intertree variability of the 87Sr/86Sr ratio in two apple orchards in South Tyrol and its relation with the soil 87Sr/86Sr ratio. In both orchards, a moderate homogeneity of the 87Sr/86Sr ratio was observed among subsamples of the same tree part (shoot axes, leaves, apple peels, and pulps). Moreover, the 87Sr/86Sr ratio homogeneity among tree parts was high intratree and low intertree. The variability of the 87Sr/86Sr ratio within the tree and within the orchard is explained in light of the 87Sr/86Sr ratios of the soil. This 87Sr/86Sr variability within orchards does not preclude its use as a geographical tracer; however, this aspect should be evaluated to correctly design a sampling campaign or to generalize the results.

The Sr/Sr ratio of a produce is generally linked with the soil geological features of the growing areas. This study aimed at assessing to which extent the addition of external Sr by agricultural practices, like irrigation and mineral nutrient supply, influences this relationship. In a first experiment, oat plants in two soils reflected the Sr/Sr of the soil. However, this link was significantly altered at increasing levels of external Sr soil supplies. In a second experiment, apple trees transplanted in pots modified their original Sr/Sr, which became progressively closer to the soil Sr isotope ratio. The addition of tap water and fertilizers, with different Sr isotopic signatures, slightly affected plant Sr/Sr. Results confirm the potential of the Sr/Sr ratio as a geographical tracer of agricultural commodities, but whenever the range of Sr/Sr variability among soils from different geographical areas is narrow, the influence of external Sr-sources may smooth over these diversities.

Understanding root water uptake sources in agricultural systems is becoming increasingly important in the sustainable management of water resources under changing climatic conditions. In this work, a stable isotope approach was adopted to investigate water sources accessed by apple trees in two orchards growing in two different locations in the upper Etsch/Adige valley (Eastern Italian Alps). We tested the general hypothesis that soil water, composed of a mixture of rain and irrigation water, was the main source for tree transpiration in both fields, but trees could also access groundwater according to the different proximity to the groundwater table of the two orchards. Our results revealed that apple trees during the 2015 and 2016 growing seasons relied mostly on soil water present in the upper 20–40 cm of soils, with an apparently negligible contribution of groundwater, irrespective of the field location in the valley bottom. The isotopic composition of xylem water did not reflect irrigation water composition (or that of groundwater) but rather of rainfall and throughfall, and soil water. We related this behaviour to the intense rate of soil evaporation during the growing period that modified the original isotopic signature of irrigation water in the shallower layers, masking its actual contribution. This work contributes to improving the understanding of water uptake strategies in Alpine apple orchards and paves the way for further analysis on the proportion of irrigation and rainwater used by apple trees in mountain agroecosystems.

BACKGROUND Apples have a leading role in the Italian fruit sector, and high‐quality apples, including the Golden Delicious variety, are cultivated mainly in the Northern mountain districts. In the present study, Golden Delicious apples from PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) cultivation districts were characterized according to their Sr isotope composition and compared with apples from other Northern Italian districts. RESULTS Apples collected in two consecutive years (2017 and 2018) confirmed the low annual variability of the 87Sr/86Sr ratio. The isotope ratio of apples was highly correlated with that of the soil extracts of the respective orchards. Statistical differences were highlighted between cultivation districts. However, because similar geological features characterized some areas, their ratios overlapped and a complete separation of the districts was not possible. CONCLUSION The 87Sr/86Sr ratio is an excellent marker for studies of food traceability because it retains the information about the place of origin. However, its strength is limited when comparing products from cultivation areas sharing similar geological features. In the perspective of geographical traceability, a multichemical characterization can overcome the limits of single‐parameter approach. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.