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The sensory, microbial and bioactive quality changes of untreated (CTRL) and mild heat−treated (HT; 90 ºC/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 ºC). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelf−life (CTRL/HT) of 18/55 (at 5 ºC), 4.5/12 (at 15 ºC), 2.4/5.8 (at 25 ºC) days. The yeast and moulds growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HT−5/15 ºC. HT and 5 ºC−storage stabilized the phenolics content. FRAP reported the best correlation (R2=0.94) with the studied bioactive compounds, followed by ABTS (R2=0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R2=0.49). Conclusively, modelling was used to estimate the shelf−life of a smoothie based on quality retention after a short time−high temperature heat treatment that better preserved microbial and nutritional quality during storage. The financial support of this research was provided by the Ministerio Español de Economía y Competitividad MINECO (Projects AGL2013−48830−C2−1−R and AGL2013−48993−C2−1−R) and by FEDER funds. G.A. González−Tejedor thanks to Panamá Government for the scholarship to carry out his PhD Thesis. A. Garre (BES−2014−070946) is grateful to the MINECO for awarding him a pre−doctoral grant. We are also grateful to E. Esposito and N. Castillejo for their skilful technical assistance.

The effect of a pasteurization treatment at 90 2 C for 35 s provided by continuous microwave under different doses (low power/long time and high power/short time) or conventional pasteurization on the quality of orange-colored smoothies and their changes throughout 45 days of storage at 5 C was investigated. A better color retention of the microwave pasteurization- treated smoothie using high power/short time than in conventionally processed sample was evidenced by the stability of the hue angle. The continuous microwave heating increased the viscosity of the smoothie more than the conventional pasteurization in comparison with non-treated samples. Lower residual enzyme activities from peroxidase, pectin methylesterase and polygalacturonase were obtained under microwave heating, specifically due to the use of higher power/shorter time. For this kind of smoothie, polygalacturonase was the more thermo-resistant enzyme and could be used as an indicator of pasteurization efficiency. The use of a continuous semi-industrial microwave using higher power and shorter time, such as 1600 W/206 s and 3600 W/93 s, resulted in better quality smoothies and greater enzyme reduction than conventional thermal treatment. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors would like to thank the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (MINECO-FEDER, AGL2013-48830- C2-1-R) for financial support

Background. Some algae are an excellent sources of vitamin B12, of special interest for vegetarian/vegan consumers, and of fucose to supplement fruit and vegetable beverages such as smoothies. Nevertheless, supplementation of smoothies with algae may lead to possible quality changes during smoothie shelf life that need to be studied. Therefore, the quality changes in fresh green smoothies supplemented (2.2%) with nine edible algae (sea lettuce, kombu, wakame, thongweed, dulse, Irish moss, nori, Spirulina and Chlorella) were studied throughout 24 days at 5 °C. Results. The initial vitamin C content – 238.7–326.0 mg kg−1 fresh weight (FW) – of a 200 g portion of any of the smoothies ensured full coverage of its recommended daily intake, and still supplying 50–60% of the recommended intake after 7 days. Chlorella and Spirulina smoothies showed the highest vitamin B12 content (33.3 and 15.3 µg kg−1 FW, respectively), while brown algae showed fucose content of 141.1–571.3 mg kg−1 FW. These vitamin B12 and fucose contents were highly maintained during shelf life. Conclusion. The Spirulina supplementation of a 200 g smoothie portion ensured full coverage of the recommended vitamin B12 intake, with lower vitamin C degradation, during a shelf life of 17 days. Furthermore, thongweed and kombu are also considered as excellent fucose sources with similar shelf life. The authors are grateful to Spanish Ministry of Economy and Competitiveness, Project AGL2013−48830−C2−1−R and FEDER for financial support. We would also like to thank SAKATA SEED IBERICA S.L. for providing Bimi® samples.

A green fresh vegetables smoothie rich in health-promoting compounds was developed. Two thermal treatments to reduce microbial load and preserve quality were assayed: T1 (3 min at 80ºC) and T2 (45 s at 90ºC). Fresh blended unheated samples were used as control (CRL). The smoothie presented a viscoelastic behaviour. Thermal treatments reduced initial microbial loads by 1.3-2.4 and 1.4-3.1 log units, respectively. Samples were stored in darkness at 5 and 15ºC. Colour and physicochemical changes were reduced in thermal-treated samples throughout storage, which were better preserved at 5ºC rather than at 15ºC. Vitamin C changes during storage were fitted with a Weibullian distribution. Total vitamin C losses of T1 and T2 samples during storage at 15ºC were greatly reduced when they were stored at 5ºC. Initial total phenolics content (151.1 mg 29 kg-1 fw) was 44 and 36% increased after T1 and T2 treatments, respectively. The 3-p-30 coumaroyl quinic and chlorogenic acids accounted the 84.7% and 7.1% relative 31 abundance, respectively. Total antioxidant capacity (234.2 mg Trolox equivalent kg-1 fw) remained constant after the thermal treatments and was better maintained during storage in thermal-treated samples. Glucobrassicin accounted the 81% of the initial total glucosinolates content (117.8 mg kg-1 fw) of the smoothie. No glucosinolates losses were observed after T2 treatment being better preserved in thermal-treated samples. Conclusively, a short time–high temperature mild thermal treatment (T2) showed better quality and bioactive compounds retention in a green fresh vegetable smoothie during low temperature storage. The authors are grateful to Spanish Ministry of Economy and Competitiveness (MINECO) Project AGL2013-48830-C2-1-R and FEDER for financial support. We are grateful to M. Otón for his skilful technical assistance.