Innovative Quality Improvement by Continuous Microwave Processing of a Faba Beans Pesto Sauce

Improvement of Selected Quality and Safety Traits in Turmeric-Enriched Kale Pesto Using Blue Light and Sous-Vide

The potential of blue light (BL) and sous-vide (S-V) as a novel approach for food preservation was investigated via measurements of the total phenolic content (TPC), antioxidative activity, color, and their antibacterial effect on Listeria monocytogenes in two versions of laboratory-prepared kale pesto, with and without the addition of turmeric. The TPC ranged from 85 to 208 mg/100 g GAE d.m. and 57 to 171 mg/100 g GAE d.m., respectively. In both versions, the highest TPC was in the blue light-sous-vide samples, while the lowest was after the sous-vide, with a loss of polyphenols of almost 40% during storage when turmeric was absent. Antioxidative capabilities of the pesto were initially estimated at 54.07 and 7.46 µmol TE/g d.m., respectively, indicating significant bioactivity enhancement by turmeric. In turmeric-enriched pesto, sous-vide decreased the antioxidative activity levels by 12% in fresh pesto and by 45% during storage. Meanwhile, blue light compensated for the losses caused by the sous-vide treatment. Although the hue angle (h°) of sous-vide pesto was lower than that of blue light pesto in most samples, sequential BL and S-V ultimately yielded the lowest h°. The sequential BL and S-V treatment resulted in a 1.7 log reduction in the L. monocytogenes population, whereas adding turmeric increased the treatment efficacy by another 2.0 logs. Thus, as a source of photosensitizing molecules, turmeric was highly antibacterial after photothermal activation with blue light and sous-vide. This study suggests that blue light could be an effective (pre)treatment used on pesto sauces to preserve bioactivity and to improve safety when enriched with a natural additive like turmeric.

Effects of 910 MHz Solid-State Microwave Cooking on the Quality Properties of Broccoli (Brassica olearacea L. var. Italica Plenck), Carrots (Daucus carota subsp. Sativus), and Red Peppers (Capsicum annuum L. cv. Kapya)

Domestic microwave ovens offer rapid cooking but face challenges such as non-uniform temperature distribution and hot spots. A novel solid-state heating system, which precisely controls microwave frequency and power, provides a promising alternative to traditional microwave ovens utilizing magnetron systems. This study compared the effects of solid-state microwave cooking on the quality of broccoli, red peppers, and carrots with those of traditional microwave and conventional cooking. The traditional microwave cooking used in this study operated at 2450 MHz, while the solid-state system functioned between 902 and 928 MHz. Weight loss was highest for conventional cooking, reaching a maximum of 34%, whereas microwave cooking resulted in a maximum of 11.65% and solid-state microwave cooking in 17.04%. The total phenolic content obtained through conventional cooking ranged between 61.58 and 116.51 mg GAE (gallic acid equivalents)/100 g dry basis, while microwave cooking resulted in a range of 88.04-110.92 mg, and solid-state microwave cooking achieved values between 76.14 and 122.91 mg. Furthermore, reductions in chlorophyll content were observed to be 68.2%, 25.6%, and 35.7% for conventional, microwave, and solid-state microwave cooking, respectively. Lycopene content after conventional cooking decreased to 224.73 mg/100 g dry basis, compared to 289.55 mg after microwave cooking and 242.94 mg after solid-state microwave cooking. β-carotene content showed a decrease of 14.5% in conventional cooking, while both microwave methods showed an increase of 14.7%. These results suggest that solid-state microwave cooking may have promising positive effects on food quality.

Physicochemical characteristics and structural changes of fermented faba bean extrudates prepared by twin-screw extrusion

In this study, fermented faba bean blends with different locust bean gum (LBG) contents were processed in a co-rotating twin-screw extruder. The effects of extrusion process variables and the LBG level on physicochemical, sensory and structural characteristics of expanded extrudates were investigated. The results showed that physical characteristics of extrudates including expansion, apparent density and texture were significantly affected by variation of screw speed and die temperature, but the effect of LBG level was only significant for expansion and density. FTIR-ATR analysis revealed that a significant change occurred in the protein secondary structure as well as in the short-range ordered molecular structure of starch during fermentation and extrusion. The X-ray diffraction patterns of extrudates exhibited V-type pattern. Microstructure of the extrudates analyzed by FE-SEM exhibited variations in cell size and wall thickness depending on extrusion processing conditions and LBG level, which in turn lead to different textural perceptions.

Effect of Microwave Heat Processing on Nutritional Indices, Antinutrients, and Sensory Attributes of Potato Powder-Supplemented Flatbread

This study aims at evaluating nutritional, toxicological, and sensory attributes of microwave heat-treated potato powder-supplemented unleavened flatbread. Straight-grade wheat flour (SGF) was substituted with potato powder at the rate of 2.5–10% d.w. A comparison was made for nutritional, antinutrient, and organoleptic attributes of microwave heat-treated potato powder and SGF—potato powder composite flour-based flatbreads. The results suggest processed potato powder supplementation in SGF to significantly ( $p<0.05$ ) improve ash (0.48 to 0.63 g/100 g), dietary fiber (2.15 to 2.61 g/100 g), and protein (8.33 to 9.91 g/100 g) contents of composite chapatis. Likewise, significant ( $p<0.05$ ) improvement in the concentration of microelements and trace elements was observed including Ca, Na, K, Fe, and Zn contents, which were increased from 29.7 to 33.5 mg/100 g, 2.8 to 6.3 mg/100 g, 376 to 466 mg/100 g, 3.1 to 3.4 mg/100 g, and 3.17 to 3.25 mg/100 g, respectively. Microwave heating of potato powder was observed to reduce the load of alkaloids, oxalates, tannins, and phytates of the raw potato powder at the rate of 76%, 80%, 84%, and 82%, respectively, thus anticipating a promising response to minimize toxicant load in supplemented flatbread. Supplementing potato powder in SGF elucidated significant ( $p<0.05$ ) improvement in color values, i.e., a∗ (1.89–2.32) and b∗ (10.95–13.22), and increased product hardness from 3.17 to 7.9 N. The study concludes that microwave heat-treated potato powder yield improved nutritional and safety concerns of the consumers when used alone or as a supplement for developing composite flours based on value-added products.

Enhancing the Efficacy of Microwave Blanching-cum-black Mould Inactivation of Whole Garlic (Allium sativum L.) Bulbs Using Ultrasound: Higher Inactivation of Peroxidase, Polyphenol Oxidase, and Aspergillus niger at Lower Processing Temperatures

The freshly harvested whole garlic bulbs require the inactivation of peroxidase (POD), polyphenol oxidase (PPO), and Aspergillus niger. However, the conventional hot water blanching and modern pretreatment like ultrasound (US) and microwave (MW) cannot individually inactivate both the enzymes and Aspergillus niger to the desired levels without compromising the quality of the garlic due to either of the higher process temperatures (> 85 °C) or prolonged treatment times. Therefore, a two-stage sequential US followed by MW pretreatment for garlic bulbs was developed for simultaneous inactivation of POD, PPO, and Aspergillus niger to the desired levels and overcome the individual pretreatment drawbacks. The separate experiments were conducted for US and MW pretreatment using central composite design, and optimization was carried out using response surface methodology. When temperature constraint was considered during optimization, the US was able to reduce POD, PPO, and Aspergillus niger by 80.87%, 93.80%, and 2.60 logs, respectively, whereas MW reduced POD, PPO, and Aspergillus niger by 77.84%, 77.04%, and 1.90 logs, respectively. The US treatment (58.43 WL⁻¹ ultrasound power density for 40 min with an initial bath temperature of 60 °C) followed by MW treatment (3 Wg⁻¹ MW power density for 120 s) resulted in 90.37% POD and 92.38% PPO inactivation with 2.62 log reduction in Aspergillus niger. The maximum temperature reached in US + MW process was 83 °C which ensured no severe thermal damage to the garlic bulbs. The scanning electron microscopic images indicated that ultrasonication induced the porous structure in garlic and helped microwaves increase the product temperature rapidly and achieve the higher inactivation of enzymes and Aspergillus niger. Thus, the US was found to be enhancing the efficacy of the MW heating process.

Revalorized broccoli by-products and mustard improved quality during shelf life of a kale pesto sauce

The effect of revalorized Bimi leaves (B) and/or mustard (M) addition, as supplementary ingredients, to develop an innovative kale (K) pesto sauce was studied. Microbial, physicochemical (color, total soluble solids content -SSC-, pH and titratable acidity -TA-) and sensory quality were studied during 20 days at 5 °C. Bioactive compounds changes (total phenolics, total antioxidant capacity and glucoraphanin contents) were also monitored throughout storage. The high TA and pH changes in the last 6 days of storage were avoided in the K+B pesto when adding mustard, due to the antimicrobial properties of this brassica seed. SSC was increased when B + M were added to the K pesto, which positively masked the kale-typical bitterness. Mustard addition hardly change yellowness of the K pesto, being not detected in the sensory analyses, showing K+B+M pesto the lowest color differences after 20 days of shelf life. The addition of Bimi leaves to the K pesto enhanced its phenolic content while mustard addition did not negatively affect such total antioxidant compounds content. Finally, mustard addition effectively aimed to glucoraphanin conversion to its bioactive products. Conclusively, an innovative kale pesto supplemented with Bimi by-products was hereby developed, being its overall quality well preserved up to 20 days at 5 °C due to the mustard addition.

Viability of sous vide, microwave and high pressure processing techniques on quality changes during shelf life of fresh cowpea puree

An innovative cowpea puree containing 78.8% of fresh cowpea seeds was developed. Microwave treatment (8 kW/35 s), high hydrostatic pressure (550 MPa/10 min/23 ℃) or sous vide treatment (80 ℃, 3 min) were assayed as processing techniques. Blended fresh cowpea samples were used as control. Quality changes during 21 days at 5 ℃ were studied. Sous vide samples showed a relevant loss during storage of viscoelastic parameters, like elastic modulus (G') and viscous modulus (G″), which was also perceived in the sensory evaluation. On the contrary, high hydrostatic pressure and microwave treatments were able to preserve consistency, texture and taste. However, physicochemical properties, mainly colour, were greatly influenced by thermal treatments, although high hydrostatic pressure treatment preserved greenness. Total phenolic content and total antioxidant capacity were more affected by high hydrostatic pressure than by microwave treatments. In conclusion, microwave and high hydrostatic pressure processing treatments seem to be quite interesting techniques to develop legume-based products.

Characterization, inhibitory activity and mechanism of polyphenols from faba bean (gallic-acid and catechin) on α-glucosidase: insights from molecular docking and simulation study

The chemo-profiling of ethanolic extract of faba beans seeds was performed and explored as an α-glucosidase inhibitor. The inhibition of α-glucosidase is one of the alternatives approach to control postprandial hyperglycemia by, resulting in the delay of the carbohydrate digestion of absorbable monosaccharides. Ethanolic seed extract showed phenolic compounds, flavonoid such as gallic acid (m/z [M- H] = 169.0124,C₇H₆O₅) ellagic acid derivatives epigallocatechin (m/z [M- H = 305.0644,C₁₅H₁₄O₇),catechin (m/z [M- H] = 289.0656,C₁₅H₁₄O₆), epigallocatechin gallate (m/z [M- H] = 457.0578,C₂₂H₁₈O₁₁) and epicatechin monogallate (m/z [M- H] = 441.081, C₂₂H₁₈O₁₀). The extract was found to exert inhibitory activity (88.28 ± 2.67%) (IC₅₀ value of 2.30 ± 0.032 mg/mL) with a mixed mode of inhibition (Km, apparent = 0.54 ± 0.020 mM and Vmax, apparent 0.136 ± 0.04 mM/min). Molecular docking studies of gallic acid and catechin on α-glucosidase proposed productive binding modes having binding energy (-6.58 kcal/mol and -7.25 kcal/mol) with an effective number of hydrogen bonds and binding energy. Tyr63, Arg197, Asp198, Glu 233, Asn324, Asp 326 of α-glucosidase participated in binding events with gallic acid and catechin. Molecular dynamics simulation studies were performed for both complexes i.e. gal:α-glucosidase and cat:α-glucosidase along with apo state of α-glucosidase, which revealed stable systems during the simulation. These findings of the present study may give an insight into the further development of the novel antidiabetic drug from the seeds of faba beans.

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

BACKGROUND

Kale is a vegetable that contains a high proportion of health-promoting compounds although its consumption as a beverage is very limited due to its bitter flavor. Nonetheless, the bitter flavor of Brassica may be masked by sweetening. The effects were studied of different stevia extracts (CTRL, S0.5 (g L^-1 ), S1.25 and S2.5) added to a kale beverage on the quality of kale juice spheres over a period of 7 days at 5 °C. Kale juice spheres were produced with a double-spherification technique, which allowed hydrogel spheres to be produced with high mechanical resistance.

RESULTS

The addition of the stevia extracts did not affect the physicochemical quality of spheres. In particular, S2.5 spheres showed the least color changes after 7 days. All spheres showed good microbiological quality throughout storage, with loads < 7 log CFU g^-1 , regardless of the stevia concentration. The sulforaphane content of kale spheres was not affected by the stevia supplementation over the 7-day period.

CONCLUSION

The addition of stevia to the kale juice spheres led to a better flavor without altering product quality during refrigerated storage. © 2018 Society of Chemical Industry.