Nitrite accumulation during storage of tomato fruit as prevented by hydrogen gas

Abstract

The adverse effects of intake nitrite upon human health are well known. However, eating fruits and vegetables is one of the main pathways to absorb nitrite because of nitrogen assimilation in plants. This study demonstrated that during storage of tomato fruit, the production of endogenous hydrogen (H 2 ) was decreased, in parallel with nitrite accumulation and the senescence rate. Furthermore, exogenously applied H 2 could delay the decreased fruit H 2 production and senescence, but importantly, nitrite accumulation was blocked. Consistently, the activities and transcripts of nitrate reductase (NR; catalyzing the synthesis of nitrite) and nitrite reductase (NiR; responsible for the reduction of nitrite to ammonium), were either inhibited or increased, respectively, by 0.585 mM H 2 . Decreased or increased nitrite synthesis was observed when tungstate (an inhibitor of NR) or 2,6-dichloroindophenol sodium salt (a putative inhibitor of H 2 synthesis) were applied separately. Time-course analysis revealed that the decrease in vitamin C, a well-known nitrite scavenger, was blocked by H 2 . Overall, this study strongly revealed that nitrite accumulation during storage of tomato fruit was prevented by H 2 . This study describes potential applications for H 2 in agriculture and food industry, especially in the preservation of fruit and vegetable products.

Magnesium Hydride-Mediated Sustainable Hydrogen Supply Prolongs the Vase Life of Cut Carnation Flowers via Hydrogen Sulfide

“…Ample evidence showed that HRW has positive effects on postharvest physiology. For example, HRW can prolong the shelf life (Hu et al, 2014) and decrease nitrite accumulation of fruits during storage (Zhang et al, 2019), as FIGURE 2 | Changes in vase life, relative fresh weight (RFW), and flower diameter of cut carnations and dissolved H 2 in solution subjected to MgH 2 , citrate buffer solution (CBS), MgH 2 -CBS, heated MgH 2 -CBS, and hydrogen-rich water (HRW). (A) Representative photographs of cut flowers (scale bar = 2 cm).…”

“…Ample evidence showed that HRW has positive effects on postharvest physiology. For example, HRW can prolong the shelf life ( Hu et al, 2014 ) and decrease nitrite accumulation of fruits during storage ( Zhang et al, 2019 ), as well as prolong the vase life of cut flowers ( Ren et al, 2017 ; Su et al, 2019 ; Wang et al, 2020 ). Importantly, the HRW is presently mainly obtained by water electrolysis, which requires a hydrogen gas generator.…”

The Applications of Molecular Hydrogen in Horticulture

“…Moreover, postharvest H 2 treatment can be beneficial for the preservation of horticultural products. Pretreatment with HRW by soaking fruits (such as kiwifruit [17], tomato [47], and lychee [18] as well as fresh-cut kiwifruit [48]) for less than 30 min can significantly maintain storage quality and prolong shelf life. H 2 fumigation for pretreatment or throughout storage period can achieve similar effects in kiwifruit [22] (Figure 1) and Chinese chive [21].…”

“…Moreover, HRW regulated the transcripts of long-distance transporters (BcNRT1.5 and BcNRT1.8) to reduce nitrate transport to shoots, resulting in decreased nitrate content in edible parts of seedlings. During postharvest storage of tomatoes, HRW can also decrease nitrite accumulation by either inhibiting or enhancing the activities and transcripts of NR and nitrite reductase (NiR), respectively [47].…”

Hydrogen Nanobubble Water Delays Petal Senescence and Prolongs the Vase Life of Cut Carnation (Dianthus caryophyllus L.) Flowers

“…Further studies have revealed that H 2 played an important role in defense responses of plants to abiotic stresses [ 13 , 14 , 15 ], plant growth [ 16 ], and secondary metabolism [ 17 ]. H 2 was beneficial to postharvest preservation of fruits (kiwifruit [ 18 , 19 ] and tomato [ 20 ]) and cut flowers (rose [ 21 ], lily [ 22 ], and Lisianthus [ 23 ]). Previous studies have reported that H 2 , dissolved in water [ 24 ] or supplied by a H 2 -releasing material (magnesium hydride [MgH 2 ]) [ 25 , 26 ], can prolong the vase life of cut carnation ( Dianthus Caryophyllus L.) flowers by enhancing activities of antioxidant enzymes and by the involvement of other gaseous signaling molecules (including nitric oxide and hydrogen sulfide).…”