Evaluation of the Harvest Dates for Three Major Cultivars of Blue Honeysuckle (Lonicera caerulea L.) in China

Abstract

Blue honeysuckle (Lonicera caerulea L.) is an emerging fruit crop; however, determining its proper harvest time in commercial cultivation remains challenging due to its rapid fruit development characteristics. In this study, we investigated 17 agronomic traits of three blue honeysuckle cultivars harvested on 5 successive dates within their respective harvest windows. ‘Lanjingling’, ‘Wulan’, and ‘Berel’ showed solid–acid ratios (SS:TA) ranging from 10.00 to 16.01, 8.13 to 10.23, and 5.77 to 7.11, respectively; anthocyanin contents ranged from 233.85 to 276.83 mg/100 g, 236.38 to 312.23 mg/100 g, and 235.71 to 334.98 mg/100 g, respectively; vitamin C contents ranged from 88.43 to 99.68 mg/100 g, 108.13 to 191.23 mg/100 g, and 89.71 to 120.40 mg/100 g, respectively; phenolic contents ranged from 25.22 to 37.59 mg/g, 25.40 to 36.52 mg/g, and 37.66 to 50.00 mg/g, respectively. The results revealed the SS:TA value consistently increased with delayed harvesting and were significantly negatively correlated with fruit firmness, total acidity, shelf life, and respiration intensity, suggesting it is an ideal maturity indicator for blue honeysuckle berries. The factor analysis suggests that the suitable harvest date for ‘Lanjingling’ could be either 47 days after flowering (DAF) with an SS:TA value of approximately 10.0, characterized by high firmness, extended shelf life, and elevated levels of anthocyanins and phenolics; or 67 DAF (SS:TA ≈ 16.0), characterized by high vitamin C content and sweetness, and larger size and weight. For ‘Wulan’, it suggests the suitable harvest date is either 54 DAF (SS:TA ≈ 9.0), yielding fruit with high levels of anthocyanins and vitamin C; or 62 DAF (SS:TA > 10.0), yielding fruit with high sweetness and large size and weight. For ‘Berel’, it is suggested to be either 52 DAF (SS:TA ≈ 6.5), resulting in fruit with high levels of anthocyanins and vitamin C; or 62 DAF (SS:TA > 7.0), resulting in balanced levels of the fruit quality traits.

Evaluation of Blue Honeysuckle Berries (Lonicera caerulea L.) Dried at Different Temperatures: Basic Quality, Sensory Attributes, Bioactive Compounds, and In Vitro Antioxidant Activity

“…However, there was an unexpected peak in a* value at 50 • C, which could be attributed to the complete loss of cuticular wax at this specific temperature or drying time. Moreover, compared with fresh blue honeysuckle berries [1,3], the dried blue honeysuckle berries showed no remarkable enhancement of SS/TA ratio, and relative to other dried small berries [18], the dried blue honeysuckle berries showed a relatively low level value of SS/TA ratio (~10). These results suggested that further dehydration-based processing of blue honeysuckle berry should involve sugaring.…”

“…The plants were cultivated for six years at the Experimental Farm of Northeast Agricultural University (NEAU) in Xiangyang town, Harbin, China (E 126 • 56 ′ 2 ′′ , N 45 • 46 ′ 10 ′′ ). On reaching commercial maturity (SS: TA ≥ 8) [3], the fruits were manually harvested and immediately subjected to a rapid field-heat removal process by the blowing of ambient air at room temperature (~20 • C) in the dark for 30 min. To minimize the removal of cuticular wax, no specific surface cleaning or washing procedures were performed.…”

“…Moreover, its exceptional agronomic traits, including remarkable freezing tolerance, ultra-early ripening, and outstanding resistance to pests and diseases, have contributed to the rapid expansion of its cultivation in cold-temperature zones of the Northern Hemisphere, such as northeast China, eastern Europe, Canada, and Hokkaido in Japan. It was estimated that its global cultivation area had reached approximately 10,000 hectares by 2022 [3]. In addition to serving as fresh fruit, blue honeysuckle berry exhibits great potential in food processing as a nutrient supplement owing to its remarkably high concentrations of bio-functional phytocompounds such as phenolics, anthocyanins, flavonoids, and vitamin C [2].…”

“…Despite its multiple distinctive advantages, blue honeysuckle berry is confronted with several challenges in both the table and processing markets due to its high vulnerability to rotting during storage and spoilage during transport. These challenges are mainly caused by intrinsically fragile skin and the remarkably tender and succulent texture of the fruit, as well as rapid postharvest senescence [3,5]. Currently, despite the wide adoption of rapid field-heat removal techniques for freshly consumed blue honeysuckle berry, long-distance transport still heavily relies on cold-chain logistics, and the average shelf-life remains shorter than one week, which leads to inevitable losses during transport [6].…”