This study addressed the critical issue of food waste, particularly focusing on carrot pomace, a by-product of carrot juice production, and its potential reutilization. Carrot pomace, characterized by high dietary fiber content, presents a sustainable opportunity to enhance the functional properties of food products. The effects of physical pretreatments-high shearing (HS), hydraulic pressing (HP), and their combination (HSHP)-alongside two drying methods (freeze-drying and dehydration) on the functional, chemical, and physical properties of carrot pomace were explored. The results indicated significant enhancements in water-holding capacity, fat-binding capacity, and swelling capacity, particularly with freeze-drying. Freeze-dried pomace retained up to 33% more carotenoids and demonstrated an increase of up to 22% in water-holding capacity compared to dehydrated samples. Freeze-dried pomace demonstrated an increase of up to 194% in fat-binding capacity compared to dehydrated samples. Furthermore, HSHP pretreatment notably increased the swelling capacity of both freeze-dried (54%) and dehydrated pomace (35%) compared to pomace without pretreatments. Freeze-drying can enhance the functional properties of dried carrot pomace and preserve more carotenoids. This presents an innovative way for vegetable juice processors to repurpose their processing by-products as functional food ingredients, which can help reduce food waste and improve the dietary fiber content and sustainability of food products.

Ultrasound-assisted extraction (UAE) was used to extract carotenoids from the carrot pomace. To investigate the effect of independent variables on the UAE, the response surface methodology (RSM) with central-composite design (CCD) was employed. The study was conducted with three independent variables including extraction time (min), temperature (°C), and ethanol concentration (%). The results showed that the optimal conditions for UAE were achieved with an extraction time of 17 min, temperature of 32 °C, and ethanol concentration of 51% of total carotenoids (31.82 ± 0.55); extraction time of 16 min, temperature of 29 °C, and ethanol concentration of 59% for a combination of β-carotene (14.89 ± 0.40), lutein (5.77 ± 0.19), and lycopene (2.65 ± 0.12). The non-significant (p > 0.05) correlation under optimal extraction conditions between predicted and experimental values suggested that UAE is the more productive process than conventional techniques for the extraction of carotenoids from the carrot pomace.

The juice expelled from carrot, a globally produced root vegetable, leavesbehind carrot pomace (a bio- and horticultural waste) which is potentially rich source of micro-nutrients and carotenoids.However, it is discarded as waste or used as animal feed. It holds potential to be channelized to food chain by a couple of technological interventions. In this regard, present work was aimed at preparing stable emulsion based delivery system for \'green\' carotenoids extracted from carrot-pomace in flaxseed oil (a green solvent), and at maximizing the amount of core material so that the resultant emulsion can potentially be used as a source of both carotenoids and omega-3 fatty acid of flaxseed oil origin. The study used natural emulsifier. Preparation of oil-in-water emulsion was optimized using 33 factorial experiment by varying levels of extract containing carotenoid (30-40%), whey protein concentrates (WPC-80) and lactose. The optimized emulsion (CREm) was selected on the basis of particle size, zeta potential, color values (L*, a*, b*) and viscosity statistically analyzed via three-way ANOVA using Proc GLM of SAS 9.3 (described in detail in this paper); the respective values of these parameters being 120.03 ± 8.20 nm, -16.57 ± 0.49 mV, 75.11 ± 0.04, 9.66 ± 0.32, 50.29 ± 0.62, and 0.124 ± 0.0115 Pa.s for CREm. CREm contained 35% flaxseed oil, 10% WPC-80 and 5% lactose and showed good centrifugal and gravitational stability (15 days). It was analyzed for total carotenoid content, antioxidant activities (ABTS (2,2-azinobis-(3-ethylbenzthiazoline-6sulfonic acid), DPPH (2,2-Diphenyl-1-picrylhydrazyl) and FRAP (Ferric reducing antioxidant power assay)) and microstructure.

Carrot pomace and finger millet flour were used to enrich the nutritional potential of biscuits with fiber. Their combined effect on physiochemical properties was optimized by response surface methodology. Experiments were conducted to standardize the formulation for development of fiber enriched biscuits using carrot pomace powder and finger millet flour at different baking times. Box-Behnken design was selected for modeling of the three independent variables: carrot pomace powder (10 g, 15 g, 20 g), finger millet flour (2.5 g, 5 g, 7.5 g), and baking time (21 min, 23 min, 25 min). Various experimental runs were used to evaluate the effect of above independent variables on spread ratio, change in colour, moisture content, ash content, fat content, fiber content, hardness and general acceptability. The optimum values predicted 15.522 g of carrot pomace powder, 5.178 g of finger millet flour and 21 min of baking time for development of enriched biscuits with 7.51 spread ratio, 17.02 change in colour, 2.85 g/100g moisture (wet basis), 14.84 g/100g fat, 2.56 g/100g ash, and 2.28 g/100g fiber, 61.967 N hardness, 8.424 general acceptability.

The effects of feed moisture content (14, 17 and 20% db), die temperature (120, 145 and 170 °C) and carrot pomace content (10, 17.5 and 25%) on the sectional expansion index, hardness, porosity, micro and macro structure and sensory properties of high fiber expanded barley-carrot pomace snack were investigated using a central composite design. Results showed that with increasing the moisture content the hardness of the extruded snacks increased while their expansion ratio decreased. The hardness decreased with increasing the die temperature, but the expansion ratio increased with increasing the die temperatures to up to 145 °C and decreased afterwards. An increase in carrot pomace content decreased the expansion ratio and cell average size while the hardness and cell wall thickness increased. The optimum condition for production of expanded barley-carrot pomace snack was 10% carrot pomace content, 142.7 °C die temperature and 14.02% moisture content. During extrusion cooking, the soluble dietary fiber of barley-carrot pomace snack increased, but no change on the total dietary fiber content was observed. Therefore, the extruded snacks prepared from barley flour and carrot pomace had high nutritional value.

The bio-wastes (like peels, seeds, etc.) from food industry are rich source of bio-active components, but are poorly managed. In present study, carotenoids were extracted from carrot pomace using ultrasonication and high shear dispersion techniques and flaxseed oil as green solvent (green biorefinery approach). Various combinations of time and temperature were used and final selection was made on the basis of maximum recovery of carotenoids. High shear disperser yielded maximum carotenoids (recovery 94.8 ± 0.08%). The total carotenoid content, antioxidant activity as ABTS, DDPH and FRAP and β-carotene of carotenoid rich extract from carrot pomace (CREP) were 82.66 ± 0.06 μg/g, 1596.04 ± 69.45 μg Trolox eq./ml, 380.21 ± 39.62 μg Trolox eq./ml, 941.20 ± 19.91 μM Trolox eq./ml, 78.37 μg/g, respectively were significantly higher (p < 0.05) when compared with the extracting medium. The L*, a* and b* values of CRE were 18.65 ± 0.037, 19.42 ± 0.21, 27.947 ± 0.65 and were significantly higher than extracting medium. The CRE could be used as a natural source of β-carotene and natural colorant for food applications.

Coniochaeta hoffmannii was isolated from soils contaminated with biscuit factory wastes showed the maximum lipid accumulation capacity in the study. Lipid production was optimized in terms of pH, carrot pomace loading, nitrogen type and amount, incubation time. Solvent, alcohol type and catalyst concentration, dried/wet biomass concentration, reaction approaches and time were optimized for lipid extraction and transesterification. The highest lipid accumulation was found as 52.0% at pH 4 in the presence of 10% carrot pomace, 0.5 g/L cheese whey at the end of the 48 h incubation. The maximum total C16 and C18 FAME rates were detected at the 25 °C, in the presence of 4 g/L dried C. hoffmannii biomass, methanol and 3% NaOH by using the in-situ transesterification process at the end of the 0.5 h as 96.3%. This is the first report about the usage of C. hoffmannii lipids obtained from carrot pomace for sustainable biodiesel production.

Inulinases are an important class of industrial enzymes which are used for the production of high-fructose syrup and fructooligosaccharides. Inulin, a polyfructan, is generally employed for the production of inulinase, which is a very expensive substrate. A number of agroindustrial residues have been used for cost-effective production of inulinases. In the present study, carrot pomace was selected as a substrate for the production of inulinase by Penicillium oxalicum BGPUP-4 in solid-state fermentation. Carrot pomace is one of the good substrates for bioprocesses, because it is rich in soluble and insoluble carbohydrates. A central composite rotatable design (CCRD) used in response surface methodology was employed for the optimal production of inulinase from carrot pomace. Using CCRD, 15 runs were practiced to optimize the range of three independent variables: moisture content (70-90%), incubation time (4-6 days) and pH (5.0-7.0) for inulinase production. Carrot pomace supplemented with 0.5% inulin as an inducer, 0.2% NH4H2PO4, 0.2% NaNO3, 0.2% KH2PO4, 0.05% MgSO4·7H2O and 0.001% FeSO4·7H2O was used for the production of inulinase in solid-state fermentation at 30 °C. Inulinase production (322.10 IU per g of dry substrate) was obtained under the optimized conditions, i.e. moisture content of 90%, incubation time 4 days and pH=7.0. The corresponding inulinase/invertase (I/S) ratio (3.38) was also high, which indicates the inulolytic nature of the enzyme. Multiple correlation coefficients R for inulinase production and I/S ratio were 0.9995 and 0.9947, respectively. The R value very close to one indicates an excellent correlation between experimental and predicted results.

Carrot pomace powder (CPP) of 72 and 120 mesh sizes was incorporated in wheat flour at 10, 15 and 20 % level and its impact on flour, dough and cookie characteristics was evaluated. Protein content of the flour blends (8.84-7.88 %) decreased and fibre content (4.63-6.68 %) increased upon blending of CPP in wheat flour. Wheat flour containing 120 mesh CPP showed better functional properties [water absorption (1.16-1.47 %), oil absorption (1.11-1.39 %), solubility index (41-50 %) and swelling power (1.34-1.39)] than those containing 72 mesh. Water solvent retention capacity and sucrose solvent retention capacity increased while lactic acid solvent retention capacity and sodium carbonate solvent retention capacity decreased with blending of CPP. Water absorption, dough development time and degree of softening increased whereas, dough stability and mixing tolerance decreased with increasing CPP. The highest decrease in pasting was observed flour containing 72 mesh CPP. Rheology of dough containing 120 mesh CPP closely resembled the control. Color of flour and cookies increased with blending of CPP irrespective of mesh size. Antioxidant activity of cookies was higher than the flour blends. The cookies containing CPP of 72 mesh showed the lowest hardness. However, cookies containing CPP of 120 mesh showed the best sensory properties. Incorporation of 120 mesh CPP produced low gluten cookies with manageable flour and dough characteristics and better antioxidant and sensory properties.

In this study, the central composite design for four variables in five levels was applied to determine the effects of pH (0.5-2.5), temperature (50-90°C), heating time (30-150min) and liquid/solid ratio (10-50v/w) on the yield and degree of esterification (DE) of carrot pomace pectin. The results showed that the pectin yield ranged from 5.0 to 15.2% and also, this pectin is classified as low methoxyl pectin (DE of 22.1-51.8%). The pH of 1.3, temperature of 90°C, time of 79.8min and liquid/solid ratio of 23.3v/w were determined as optimal conditions with a maximum yield of 15.6±0.5%, which was close to the predicted values (16.0%). Under the optimal extraction conditions, the galacturonic acid content and emulsifying activity were 75.5 and 60.3% respectively; moreover, the emulsions had a high stability at two different storage temperatures (4 and 23°C). Furthermore, carrot pectin solutions exhibited viscous and pseudoplastic behavior at 1% w/v.