Preservation of bioactive compounds of a green vegetable smoothie using short time–high temperature mild thermal treatment

Abstract

Smoothies represent an excellent and convenient alternative to promote the daily consumption of fruit and vegetables in order to obtain their health-promoting benefits. Accordingly, a green fresh vegetables smoothie (77.2% cucumber, 12% broccoli and 6% spinach) rich in health-promoting compounds was developed. Soluble solids content, pH and titratable acidity of the smoothie were 4.3 ± 0.4°Bx, 4.49 ± 0.01 and 0.22 ± 0.02 mg citric acid 100 g fw, respectively. Two thermal treatments to reduce microbial loads and preserve quality were assayed: T1 (3 min at 80 ℃) and T2 (45 s at 90 ℃). Fresh blended unheated samples were used as control (CTRL). The smoothie presented a viscoelastic behaviour. T1 and T2 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 15 ℃. Colour and physicochemical changes were reduced in thermal-treated samples throughout storage, which were better preserved at 5 ℃ rather than at 15 ℃. Vitamin C changes during storage were fitted with a Weibullian distribution. Total vitamin C losses of T1 and T2 samples during storage at 15 ℃ were greatly reduced when they were stored at 5 ℃. Initial total phenolic content (151.1 ± 4.04 mg kg fw) was 44 and 36% increased after T1 and T2 treatments, respectively. The 3-p-coumaroyl quinic and chlorogenic acids accounted the 84.7 and 7.1% relative abundance, respectively. Total antioxidant capacity (234.2 ± 20.3 mg Trolox equivalent kg 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 ± 22.2 mg kg 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.

Effect of stevia supplementation of kale juice spheres on their quality changes during refrigerated shelf life

“…The soluble solids content (SSC), pH and TA were determined using the devices and methodologies previously described . Color was determined with a colorimeter (Chroma Meter CR‐400, Konica Minolta, Japan) using the illuminant D65, 2° observer, and an 8 mm viewing aperture.…”

Natural vitamin B12 and fucose supplementation of green smoothies with edible algae and related quality changes during their shelf life

“…This finding may be explained by the higher content of SSC, mainly sugars, of brown and red algae compared to green algae , . The CTRL smoothie showed an initial pH of 4.24, such an acidic medium allowing a moderate shelf life of the beverage under refrigeration conditions without the need for thermal treatments, which may reduce the sensory and nutritional/bioactive quality of the smoothie. Algae supplementation of smoothies led to a slight pH increase up to 4.32–4.77 owing to the high mineral content of algae, which may constitute up to 40% of the total weight .…”

Effect of abiotic stresses on bioactive contents of vegetables and high-pressure technology in related functional beverages

“…Latter TAC decrease may be correlated to the vitamin C degradation of samples since high TACvitamin C correlations of 75 and 34 % have been reported in melon and pineapple, respectively (Guo et al, 2003). TAC of BD0 and BD4 beverages decreased by 10-23 % after 48 h. Correspondingly, vitamin C of red vegetable smoothies was decreased by 40 % after 4 days at 5 ºC (Castillejo et al, 2016b). Such TAC losses after 48 h were even aggravated in BD7 samples with a TAC reduction of 40-50%.…”

“…The higher cost of the refrigerated distribution and domestic conservation may be justified with the high sensory and nutritional/bioactive quality of the product. For example, a thermal treatment of 90 ºC for 45 s of a green vegetables smoothie ensured a shelf life of 45 days at 5 ºC being their nutritional/bioactive compounds highly preserved (Castillejo et al, 2016a). Furthermore, a 250-g portion of latter smoothie may highly cover the minimum daily recommended intakes of fibre, minerals and vitamin C (FAO/WHO, 2004) for different segments of the population with difficulties to consume fresh fruit and vegetables.…”

“…Physicochemical quality was determined based on pH, TA, SSC and CIE Lab colour parameters determined with the same equipment and methodology described by Castillejo et al (2016a). Total colour differences (ΔE) throughout storage, compared to their respective initial values, were calculated as previously described (Tontul et al, 2016).…”