Comparative evaluation of postharvest preservation strategies for Brussels sprouts (Brassica oleracea var. gemmifera)

Introduction

Brussels sprouts (Brassica oleracea var. gemmifera) are a highly nutritious vegetable generally recognised for high dietary fibre, vitamin K and C content, essential minerals, and glucosinolaterich phytochemical profile, which collectively contribute to antioxidant, anti-inflammatory, and potential chemoprotective effects (Doniec et al., 2022; Bhat et al., 2023) [7,2] . The Present attribute leads to an increase in demand of Brussels sprouts in both the area, whether fresh consumption, as minimally processed, as salad, or sauteed form. The functional foods continue to rise (Sagar et al., 2021; Cartea et al., 2020) [22,4] . Though demand and nutrition both are high, the Brussels sprouts are highly perishable commodities, which limits the marketability, distance transportation, storage problems, etc. (Sood et al., 2017) [26] . The losses which occur are due to high continued respiration, transpiration, and metabolic activity, which lead to moisture depletion, post-harvest quality loss, structure degradation (Caleb et al., 2013) [3] . These physiological processes are accompanied by chlorophyll breakdown, enzymatic browning, organic acid metabolism, and accumulation of off-flavor compounds, loss of firmness, ultimately resulting in yellowing, buttend discolouration, and reduced sensory acceptability (Kader, 2002) [11] . Also, high moisture content led to microbial spoilage; rapid bacterial growth caused physiological loss, discolouration, odour, and poor appearance (Shomodder et al., 2022) [25] . With all other inherent attributes of Brussels sprouts, if one can talk about one more parameter of degradation or post-harvest quality losses is the temperature, which again plays a very critical role in determining the post-harvest behaviour. Brussels sprouts can be stored for 3-5 weeks at 0°C, highlighting the strong temperature dependence of metabolic activity and senescence (Bhat et al., 2023) [2] . Though optimised cold store handling and storage protocols are available in the literature, the challenge of minimal losses and preservation with minimal processing is still in the system, and one has to explore the effectiveness of the same on the shelf life and microbial activity of Brussels Sprouts. (Lurie, 1998; Rico et al., 2007) [16,21] . The vegetables are usually subjected to a numbers of processing steps, making a processing chain for the same. These steps include pretreatment, preservation and storage of the vegetable (Vancoillie et al., 2024) [28] . It is generally recognized that each step in this processing chain can have a different impact on the vegetable's health-related compounds profile. Blanching foods helps reduce quality loss over time, done before freezing, drying or canning (Lin and Brewer, 2005.) [15] . Heating vegetables or fruits to inactivate enzymes, modify texture, remove the peel, and wilt tissue (Temiz et al., 2017) [27] . The process has three stages: preheating, blanching, and cooling. Drawbacks to the blanching process can include leaching of water-soluble and heat sensitive nutrients and the production of effluent (Sharma et al., 2025) [24] . Alternatively, antioxidant-based treatments, particularly ascorbic acid dips, have shown promise in preserving quality by reducing oxidative stress, stabilizing pigments, and maintaining cellular integrity (Eze et al., 2025) [8] . Ascorbic acid acts as an antimicrobial agent. Ascorbic acid acts as a reducing agent that limits enzymatic browning and delays senescencerelated biochemical changes (Davey et al., 2000; Lee and Kader, 2000) [6,14] . In parallel, oxidative sanitizers such as hydrogen peroxide and chlorine are widely used in fresh produce systems to reduce microbial load and enhance safety (Chinchkar et al., 2022) [5] . These chlorine solutions are useful as a disinfection tool for food surface (Gómez-López et al., 2009) [10] . Chlorination has been routinely used to treat postharvest cooling water, in postharvest treatments (i.e. calcium for firmness enhancement) and during rehydration at shipping destinations (Sargent et al., 2000). These treatments function through oxidative mechanisms that disrupt microbial cell membranes; however, their application must be carefully controlled to avoid tissue damage, oxidative stress, and regulatory concerns regarding residues and environmental impact (Gil et al., 2009; Parish et al., 2003) [9,18] . Therefore, the present study aims to evaluate the effects of blanching, ascorbic acid, hydrogen peroxide, and chlorine treatments on the postharvest quality of Brussels sprouts stored under refrigerated conditions (6-7 °C) in low-density polyethene packaging. The study focuses on key quality parameters, including pH, moisture loss, total soluble solids, and gas composition, to provide a comprehensive understanding of treatment-induced changes and to identify the most effective strategy for short-term storage and handling

Materials and Methods

Fresh Brussels sprouts were sourced from the regional research station, Punjab Agricultural University, Gurdaspur. The mature and healthy sprouts were selected. Selected sprouts were cleaned, and any damaged ones were removed. The final cleaned uniformsized Brussels sprouts were subjected to pre-treatments and packed in low-density polyethene (LDPE) bags. Storage was done at 6-7 °C. The tested treatments as per the table no. 1 were: (i) 1% ascorbic acid dip for 5 min; (ii) 10% hydrogen peroxide dip for 5 min; (iii) 200 ppm chlorine dip for 5 min; and (iv) blanching in boiling water for 3 min followed by immediate cooling. Samples were withdrawn on days 0, 4, and 8 for quality assessment. Measured quality indicators included total soluble solids (TSS), pH, colour attributes (Hunter L*, a*, b*), moisture content, bulk and true density. Total soluble solids (TSS) were measured using a hand-held refractometer after calibrating the instrument with distilled water, while pH was determined by extracting juice from crushed samples and recording the readings using a calibrated pH meter. Colour characteristics were analysed using a Konica Minolta colour reader based on Hunter Lab coordinates (L*, a*, and b* values). Gas composition analysis was performed using a GS6600 gas analyser to determine oxygen and carbon dioxide concentrations within sealed LDPE packages during storage. Moisture content changes were estimated through oven drying at 92 °C until constant weight was achieved.

Statistical analysis

The experimental data obtained during the present research work were subjected to statistical analysis. All the experimental data for the analysis of pretreated Brussels sprouts were expressed as mean ± standard deviation calculated from three independent replication experiments. One-way and two-way analysis of variance (ANOVA) was applied and the Duncan multiple range test was performed to measure the test of significance by post hoc test using the software SPSS v16.0 (SPSS Italia, Bologna, Italy).

Results and Discussion

Physical profile of the raw material

The reported physical profile confirms that Brussels sprouts in this study were compact, nearly spherical in the shape units with relatively good moisture content. Baseline properties were estimated like diameter, sphericity, moisture content, bulk density and true density. The results indicated that the crop is high in moisture content and has sensitivity to microbial growth. These baseline properties are consistent with the need for lowtemperature management and gentle handling (Table 2).

Effect of pre-treatments on color and visual quality

Color retention indicated a key discriminator among treatments.

The study showed that ascorbic acid was the best in preserving the greenness and lightness of the Brussels Sprout, whereas in comparison to other treatments, blanching caused the maximum loss of green character. Statistical analysis revealed significant differences (p < 0.05) among treatment-day combinations as shown in fig 1 . The reason is that ascorbic acid limits oxidative browning and can protect chlorophyll-containing tissues, while thermal blanching accelerates pigment disruption and can intensify visual dulling (Patras et al. 2011) [20] . Hydrogen [12,19,23] .

Effect of Pre-treatment on Total Soluble Solids

The determination of total soluble solids (TSS, °Brix) was carried out for all treatments at regular storage intervals, and the results are presented in Fig. 2. Statistical analysis revealed significant differences (p < 0.05) among treatment-day combinations. A consistent declining trend in TSS was observed across all treatments throughout the storage period, indicating progressive metabolic utilization of soluble sugars. At day 0, TSS values ranged from 5.5 ± 0.11°Brix in hot water blanched samples to 8.0 ± 0.12°Brix in ascorbic acid treated samples. During storage, a gradual decrease was recorded in all treatments; however, the rate of decline varied significantly among treatments. By day 8, the lowest TSS values were observed in hot water-treated samples (2.0 ± 0.07°Brix) followed by H₂O₂-treated samples (4.0 ± 0.08°Brix), whereas relatively higher TSS retention was recorded in control (5.0 ± 0.11°Brix), ascorbic acid-treated (6.0 ± 0.10°Brix), and chlorine-treated samples

Moisture behavior, tissue integrity, and respiratory implications

The determination of moisture loss was carried out for all treatments during storage, and the results are presented in Fig. 4. A progressive increase in moisture loss was observed across all treatments with increasing storage duration, indicating continuous water loss due to transpiration and respiration processes. Statistical analysis revealed significant differences (p < 0.05) among treatment-day combinations. At day 4, moisture loss ranged from 0.001 ± 0.0003 (hot waterblanched samples) to 0.065 ± 0.005 (ascorbic acid-treated samples). As storage progressed, moisture loss increased steadily in all treatments. By day 8, the highest moisture loss was recorded in control samples (0.090 ± 0.005), closely followed by ascorbic acid-treated samples (0.087 ± 0.006), while the lowest moisture loss was observed in hot water-blanched samples (0.002 ± 0.0002). Chlorine-treated (0.064 ± 0.003) and H₂O₂-treated samples (0.007 ± 0.002) exhibited moderate moisture loss. The data is shown in fig 4 . The increase in moisture loss during storage can be attributed to physiological weight loss caused by transpiration and respiration, which leads to depletion of cellular water content. Similar findings have been reported by Wills et al. (2016) [29] and Kader (2002) [11] , who stated that water loss is a major factor affecting postharvest quality due to continuous metabolic activity and environmental influences. Hot water blanching showed minimal moisture loss, possibly due to inactivation of enzymes and reduction in respiration rate, thereby slowing down water loss. This observation is in agreement with findings by Lurie (1998) [16] and Rico et al. (2007) [21] , who reported that heat treatments can delay senescence and reduce moisture loss in fresh produce.

Gas Composition During Storage

The composition of gases within the packaging was determined to assess the respiration behavior and metabolic activity of the samples during storage. Gas composition analysis was carried out using a gas analyzer, and the results are presented in Table 3.

Changes in oxygen (O₂) and carbon dioxide (CO₂) concentrations provide a direct indication of respiration rate, where decreasing O₂ and increasing CO₂ reflect active metabolic processes. At day 0, all treatments exhibited nearly similar atmospheric conditions, with O₂ levels ranging from 20.1 ± to 20.4 ± 0.13% and CO₂ levels around 1.0 ± 0.04% to 1.2 ± 0.05%, indicating uniform initial packaging conditions. During storage, a gradual decline in O₂ concentration and a corresponding increase in CO₂ concentration were observed across all treatments. By day 4, O₂ levels decreased notably in hot water-blanched samples (11.4 ± 0.20%) compared to control (18.3 ± 0.24%), accompanied by variations in CO₂ accumulation.

By day 8, the lowest O₂ level was recorded in hot water-blanched samples (6.85 ± 0.28%), while the highest CO₂ accumulation was also observed in this treatment (9.0 ± 0.35%), indicating a higher respiration rate or altered gas permeability.

In contrast, ascorbic acid-treated samples maintained relatively higher O₂ levels (15.7 ± 0.21%) and moderate CO₂ levels (6.5 ± 0.24%) by day 8, suggesting a more balanced gaseous environment and potentially reduced metabolic activity compared to other treatments. Control samples showed intermediate behavior, with O₂ decreasing to 15.8 ± 0.21% and CO₂ increasing to 4.4 ± 0.27%. The observed trend of decreasing O₂ and increasing CO₂ is consistent with respiration processes, where oxygen is consumed and carbon dioxide is produced. Similar findings have been reported by Kader (2002) [11] and Caleb et al. (2013) [3] , who demonstrated that gas composition changes in packaged produce are directly linked to respiration rate and storage conditions.

Discussion

When the observed quality domains are interpreted together, the treatments can be ranked qualitatively for fresh refrigerated storage as follows: ascorbic acid is the best, followed by chlorine, which was equivalent to hydrogen peroxide, and the worst was blanching. Blanching may still have value in processing chains designed for freezing or cooking, but the dataset does not support it as the preferred option for retaining fresh-like quality during short refrigerated storage. Among the different preservation treatments evaluated for Brussels sprouts, ascorbic acid treatment showed the highest overall suitability for refrigerated storage due to its antioxidant and anti-browning properties. It demonstrated superior colour retention, better stability of total soluble solids (TSS) and pH, and comparatively lower respiration activity, although optimization of concentration and treatment duration is still required. Hydrogen peroxide treatment functioned primarily as an oxidative sanitizer and offered effective microbial control with the added advantage of decomposing into water and oxygen without harmful residues; however, excessive concentrations may induce tissue stress and its efficiency depends largely on concentration stability. A comparative table 4 is showing all the data. Chlorine treatment was also effective as an antimicrobial wash and is widely adopted in industrial applications because of its simplicity and cost-effectiveness, but concerns related to pigment degradation, chemical residues, and changing regulatory preferences limit its desirability. Blanching, which relies on thermal enzyme inactivation, is generally more suitable for products intended for freezing or further processing rather than fresh refrigerated storage, as it may cause nutrient leaching, texture softening, and pigment degradation, resulting in comparatively poor fresh-storage performance.

Conclusion

The evidence base converges on a clear conclusion: among the tested pre-treatments, ascorbic acid is the best candidate for maintaining short-term refrigerated quality of Brussels sprouts intended for fresh consumption. Its benefits include color preservation, pH moderation, TSS retention, and reduced apparent respiratory stress, whereas blanching is comparatively unsuitable for fresh-storage objectives. The study further indicates that next-generation Brussels sprout preservation should combine optimized low-temperature storage with safer sanitation systems, acid-based anti-browning strategies.

Acknowledgement

Acknowledgements:We acknowledge department of Processing and Food Engineering for providing research facilities.

References

1. Ali S, Khan AS, Malik AU, Shahid M. Postharvest application of ascorbic acid maintains quality and reduces oxidative damage in fruits. Postharvest Biology and Technology. 2022;187:111865.
2. Bhat R, Deshpande R, Sridhar KR. Postharvest quality and nutritional changes in cruciferous vegetables. Journal of Food Composition and Analysis. 2023;115:104964.
3. Caleb OJ, Mahajan PV, Al-Said FAJ, Opara UL. Modified atmosphere packaging technology of fresh and fresh-cut produce and the microbial consequences-A review. Food Engineering Reviews. 2013;5(1):1-17. doi:10.1007/s12393012-9069-0.
4. Cartea ME, Francisco M, Soengas P, Velasco P. Phenolic compounds in Brassica vegetables. Foods. 2020;9(10):1436. doi:10.3390/foods9101436.
5. Chinchkar AV, Singh A, Singh SV, Acharya AM, Kamble MG. Potential sanitizers and disinfectants for fresh fruits and vegetables: A comprehensive review. Journal of Food Processing and Preservation. 2022;46(10):e16495.
6. Davey MW, Van Montagu M, Inzé D, Sanmartin M, Kanellis A, Smirnoff N, et al. Plant L-ascorbic acid: Chemistry, function, metabolism, bioavailability and effects of processing. Journal of the Science of Food and Agriculture. 2000;80(7):825-860. doi:10.1002/(SICI)10970010(20000515)80:7<825::AID-JSFA598>3.0.CO;2-6.
7. Doniec J, Kowalska H, Czajkowska K. Nutritional and functional properties of Brassica vegetables: A review. Molecules. 2022;27(3):789.
8. Eze CN, Aduba CC, Ezema BO, Ayoka TO, Nnadi CO, Onyeaka H. The role of antioxidants in food safety and preservation: Mechanisms, applications, and challenges. Cogent Food & Agriculture. 2025;11(1):2591436.
9. Gil MI, Selma MV, López-Gálvez F, Allende A. Fresh-cut product sanitation and wash water disinfection: Problems and solutions. Annual Review of Food Science and Technology. 2010;1:341-368. doi:10.1146/annurev.food.080708.100818.
10. Gómez-López VM, Rajkovic A, Ragaert P, Smigic N, Devlieghere F. Chlorine dioxide for minimally processed produce preservation: A review. Trends in Food Science & Technology. 2009;20(1):17-26.
11. Kader AA. Postharvest technology of horticultural crops. 3rd ed. Oakland (CA): University of California Agriculture and Natural Resources; 2002.
12. Kumar P, Sharma R, Singh J. Effect of post-harvest treatments on quality attributes of fresh vegetables: A review. Journal of Food Science and Technology. 2021;58:1-12.
13. Kumar R, Sharma R, Singh D. Role of antioxidants in extending shelf life of horticultural produce. Journal of Food Composition and Analysis. 2023;115:105012.
14. Lee SK, Kader AA. Preharvest and postharvest factors influencing vitamin C content of horticultural crops. Postharvest Biology and Technology. 2000;20(3):207-220. doi:10.1016/S0925-5214(00)00133-2.
15. Lin S, Brewer MS. Effects of blanching method on the quality characteristics of frozen peas. Journal of Food Quality. 2005;28(4):350-360.
16. Noctor G, Foyer CH. Ascorbate and glutathione: Keeping active oxygen under control. Annual Review of Plant Biology. 1998;49:249-279. doi:10.1146/annurev.arplant.49.1.249.
17. Parish ME, Beuchat LR, Suslow TV, Harris LJ, Garrett EH, Farber JN, et al. Methods to reduce/eliminate pathogens from fresh and fresh-cut produce. Comprehensive Reviews in Food Science and Food Safety. 2003;2(Suppl 1):161-173. doi:10.1111/j.1541-4337.2003.tb00033.x.
18. Pathare PB, Opara UL, Al-Said FAJ. Colour measurement and analysis in fresh and processed foods: A review. Food and Bioprocess Technology. 2020;13:161-178.
19. Patras A, Tiwari BK, Brunton NP. Influence of blanching and low temperature preservation strategies on antioxidant activity and phytochemical content of carrots, green beans and broccoli. LWT -Food Science and Technology. 2011;44(1):299-306. doi:10.1016/j.lwt.2010.06.019.
20. Rico D, Martín-Diana AB, Barat JM, Barry-Ryan C. Extending and measuring the quality of fresh-cut fruit and vegetables: A review. Trends in Food Science & Technology. 2007;18(7):373-386. doi:10.1016/j.tifs.2007.03.011.
21. Sagar NA, Pareek S, Sharma S, Yahia EM, Lobo MG. Fruit and vegetable waste: Bioactive compounds, their extraction, and possible utilization. Comprehensive Reviews in Food Science and Food Safety. 2021;20(2):1514-1550.
22. Saini RK, Keum YS, et al. Advances in preservation techniques for fresh produce: Role of antioxidants and sanitizers. Postharvest Biology and Technology. 2022;188:111900.
23. Sharma K, Kumar V, Rawdkuen S, Kumar S, Chandel R. Blanching reimagined beyond enzyme inactivation: A multifunctional and sustainable approach to modern food processing. CABI Reviews. 2025;20(1):0083.
24. Shomodder Z, Rahman MM, Islam MS. Postharvest handling and microbial spoilage of leafy vegetables. Journal of Food Safety. 2022;42(4):e12987.
25. Sood M, Sharma S, Thakur K. Postharvest management of cruciferous vegetables: A review. Journal of Applied and Natural Science. 2017;9(2):1190-1196.
26. Temiz A, Ayhan DK. Enzymes in minimally processed fruits and vegetables. In: Yildiz F, Wiley RC, editors. Minimally processed refrigerated fruits and vegetables. New York: Springer; 2017. p. 93-151.
27. Vancoillie F, Verkempinck SH, Kemp L, De Maziere S, Delbaere SM, Van Poucke C, et al. Impact of frozen storage and pretreatment conditions on health-related compound stability kinetics in leeks and Brussels sprouts. LWT. 2024;204:116457.
28. Wills R, McGlasson B, Graham D, Joyce D. Postharvest: An introduction to the physiology and handling of fruit and vegetables. 6th ed. Wallingford: CABI; 2016.