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Active packaging is an innovative and effective way to extend the shelf life of food, but few studies have focused on the effect of its active ingredients on food flavor. This study aimed to develop slow-release polylactic acid/polyhydroxyalkanoates (PLA/PHA) active packaging containing oregano essential oil (OEO) and investigate the effect of active composite packaging on the flavor and quality of pufferfish fillets. The plasticizing effect of OEO increased the elongation at break (EAB) of the films from 23.36% to 65.80%. The adsorption of montmorillonite (MMT) reduces the loss of OEO during processing. The amount of active substance (carvacrol) released from PLA/PHA/OEO/MMT film to pufferfish was 9.70 mg/kg. The pufferfish fillets packed in PLA/PHA/OEO/MMT film showed the slightest difference on the 8th day from the beginning of storage. The slow-release composite films could extend the shelf life of pufferfish fillets by 2-3 days at 4 °C ± 1 °C.

Source sink balance is one of the major determinants of carbon partitioning in plants. However, its effects on photosynthesis in fruit trees are largely unknown. In this work, the effects of low sink demand on net photosynthetic rate (Pn) and chlorophyll fluorescence after fruit removal (-fruit) in peach (Prunus persica (L.) Batsch cv. ‘Zaojiubao’) trees were investigated. The stepwise energy flow through photosystem II (PSII) at the reaction center (RC) was analyzed with quantitative analyses of fluorescence transient, also called JIP-test. We found that Pn was significantly lower and closely correlated to the leaf stomatal conductance (Gs) of -fruit trees than that of fruit retained (+fruit) trees. Leaf temperature (Tleaf) of -fruit trees was remarkably higher than that of +fruit trees. Day-time-period assays of chlorophyll (Chl) fluorescence revealed that, in the leaves of -fruit trees, the fluorescence parameters, such as NPQ (non-photochemical quenching coefficient) and ΦD0 (maximum quantum yield of non-photochemical de-excitation), decreased in the morning and recovered to the normal level in the afternoon, whereas other parameters, such as ΦE0 (quantum yield for electron transport at t = 0), Ψ0 (probability that a trapped exciton moves an electron to QA pool), F0 (minimum fluorescence, when all PSII RCs are open) and Wk (relative variable fluorescence at 300 μs of the chlorophyll fluorescence transient), did not. These results suggest that OEC complex and QA pool were irreversibly affected by low sink demand, whereas light harvest antenna and PSII potential efficiency retained a strong ability to recover.

The types and amounts of volatiles in denucleated fruit of 30 Chinese dwarf cherry germplasms were determined by headspace solid-phase microextraction and gas chromatography-mass spectrometry to assess the genotypic variation. Eighty-five volatiles were identified; hexyl acetate, 4-penten-1-yl acetate, prenyl acetate, (Z)-pent-2-enyl hexanoate, geranyl acetate, n-butyl acetate, (3Z)-3,7-dimethylocta-1,3,6-triene, geraniol, pent-2-enyl butanoate, ethyl caprylate, butyl hexanoate, and linalool were the main volatiles. The type and content of volatile varied with genotype. Red fruits had the most abundant aroma and vinicolor fruits exhibited the least. Principal component analysis clustered the 30 Chinese dwarf cherry germplasms into four groups: (1) 2 germplasms (NM2 and HN3) had high ester content, (2) 24 germplasms (BJ1-BJ6, HB1, HB2, HN1, HN2, NM1, NM3, SX1, SX2, SX4-SX6, SX8-SX10, SX12, SX13, SX15, and SX16) contained mainly esters, lactones, and terpenes, (3) 2 germplasms (SX11 and SX14) had high ester and lactone content, and (4) 2 germplasms (SX3 and SX7) had high ester and terpene content.

This study aimed to develop a bilayer active film by using polyvinyl alcohol (PVA)/ethylene-vinyl acetate copolymer (EVA) and antioxidant essential oils. The effect of the bilayer active film on the quality and shelf-life of mutton was investigated. PVA laminated material was considered to improve the barrier capacity, while essential oils incorporated into EVA laminated material conferred antioxidant and antimicrobial activity. The effect of the addition of essential oils on the film by mechanical properties, oxygen permeability, scanning electron microscopy (SEM) image, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) was investigated. Releasing of active compound into mutton and antioxidant activity was investigated to evaluate the films. The antibacterial effects of bilayer active films were subsequently evaluated based on the antibacterial properties of active film and Total viable counts (TVC) of mutton. Microbial community structure in the mutton of different packaging was analyzed by Illumina MiSeq sequencing. Based on total volatile basic nitrogen (TVB-N), the shelf life of mutton was tested. The results showed that the active compound improved flexibility and ductility of active PVA/EVA films. The results also showed a high release of OEO (21.99 mg/kg) and TTO (17.96 mg/kg) as well as high antioxidant and antimicrobial efficiency of PVA/EVA films with essential oils. High-throughput sequencing has shown that the addition of OEO and TTO can reduce the type of dominant bacteria, reducing Acinetobacter by 15.8% and 15.55%, respectively. The release test of active compounds into the mutton showed that the higher contents of the active compounds released, the more microbial proliferation limited, thereby it effectively retarded the increase of TVB-N, which extended the shelf life of mutton by 5–6 days.

Due to negative impacts of non-biodegradable plastic films to the environment, biodegradable packaging materials have become a research hotspot. Novel biodegradable active films based on polylactic acid (PLA) blended with poly (butylene succinate adipate) (PBSA), carvacrol, and thymol were developed. Mechanical properties of films including tensile strength (TS), elongation at break (EAB), optical properties including transmittance (T) and haze (H), barrier properties including water vapor permeability (WVP), oxygen transmission rate (OTR), and releasing rates of active compound from films and antioxidant efficiency of films were investigated to evaluate the films. A shelf life test of salmon slices packed with PLA-PBSA bags (with and without active compound) were carried out. The results showed that PLA-PBSA based films had better mechanical properties than those of similar biodegradable films such as PLA-PHB, and even better than EVOH in terms of two major mechanical properties, TS and EAB. As to active properties, the results also showed a high release of active compound and high antioxidant efficiency of PLA-PBSA films with either carvacrol or thymol. The shelf life test of salmon slices showed the antibacterial and antioxidant properties of the PLA–PBSA films were enhanced when the active compound were released into salmon slices at equilibrium. As a result, spoilage and deterioration of the salmon slices were reduced, which extended the shelf life of salmon slices by 3–4 days during cold storage. Thus, the biodegradable PLA–PBSA films with active compound could prolong shelf life of fisheries products in particular, and food in general.

The volatiles of 75 plums belonging to five species and one interspecific hybrid were investigated by headspace-SPME–GC–MS; 88 volatiles were identified. Prunus salicina and its hybrids had much more compounds and higher contents of volatiles than Prunus domestica and other three Chinese wild species. Aldehydes were the dominant volatiles in P. domestica and Prunus spinosa while esters were the major volatiles in P. salicina, P. salicina hybrids and Prunus ussuriensis fruits. Regarding terpenoids and alcohols, they were relatively high in several P. salicina cultivars, P. salicina hybrids and P. spinosa, and in Prunus cerasifera, respectively. All the plum germplasms could be divided into three groups via principal component analysis: (1) nine cultivars of P. salicina with high ester content, (2) nine Chinese cultivars and one P. salicina hybrid with ester content and two terpenoids, and (3) the rest of the cultivars and three Chinese wild species without characteristic volatiles.

Volatile compounds of three different flavour table-grapes, ‘Jingxiu’, ‘Bimeijia’ and ‘Jingya’, were investigated during and after maturation using SPME/GC–MS. All the alcohols and carbonyls, along with most of the C6 compounds and terpenoids, were evident before veraison, while most of the esters were detected at or after veraison. C6 compounds increased in the early period of maturation, and then decreased. Most alcohols and carbonyls tended to continuously decrease during ripening. Except for geraniol, terpenoids increased until maturation, then decreased. Some esters continued to increase after maturation. Principal component analysis showed that terpenoids and esters were the characteristic volatiles of ripe ‘Bimeijia’ and ‘Jingya’ grapes, respectively. ‘Bimeijia’ had the highest terpenoid content at maturity, while ‘Jingya’ continued to accumulate some esters after maturation. To achieve berries of full-bodied aroma, ‘Bimeijia’ should be harvested at maturity and ‘Jingya’ should have a delayed harvest. For the neutral grape ‘Jingxiu’, delayed harvest is recommended to reduce the ‘green’ odour.

Grape calli systems were used to study the relationships between stilbene production and: (1) four grape genotypes, (2) leaf, berry exocarp and seed tissues and (3) UV-C irradiation. All explants could be de-differentiated. However, subsequent callus growth depended mainly on genotype and tissue type. Non-embryogenic callus accumulated more resveratrols and piceids and had a higher growth index than pro-embryogenic and embryogenic calli. UV-C irradiation for 20 min was most efficient in promoting both the accumulation of resveratrols and piceids and callus growth index. There was dynamic production of resveratrols and piceids in UV-C-irradiated leaf-derived calli over a 72 h period, with optimum harvest time for the highest total stilbene content at 48 h. Accumulation of stilbenes in UV-C-irradiated calli depended upon genetic background and tissue type, with higher stilbene contents in two interspecific root stocks and leaf or exocarp explants.

Using HS–SPME–GC–MS, characteristics of the volatiles of 50 peaches and nectarines representing different germplasm origins were investigated. Ten of these peaches and nectarines were studied in two successive years. Eighty-four compounds were identified. Volatile composition was relatively consistent, but the amount of total volatiles and certain individual compounds varied between years. Moreover, the composition of volatiles and their contents depended on genotypic background and germplasm origin. Total volatiles in wild peaches and a Chinese local cultivar ‘Wutao’ were much higher than in the other groups. All the peaches and nectarines could be classified into four groups by principal component analysis of the volatiles (excluding C6 compounds): ‘Ruipan 14’ and ‘Babygold 7’ with high contents of lactones, Chinese wild peaches and ‘Wutao’ with high contents of terpenoids and esters, seven cultivars with American or European origins with high content of linalool, and others without characteristic composition of volatiles.

Volatile aroma compounds are one of the important characteristics determining fruit quality. Evaluation of volatiles at the germplasm level is useful for future breeding efforts, aimed at improvement of fruit quality, via effects on fruit aroma. The composition and concentration of volatiles in berries of forty-two grape cultivars belonging to seven genotypic groups were evaluated by headspace solid-phase microextraction with GC–MS. Sixty volatiles were detected, of which C6 compounds were the dominant volatiles in V. amurensis grape, neutral cultivars V. vinifera grapes and hybrid grapes between V. vinifera with V. thunbergii or V. amurensis. Alcohols and carbonyls were relatively low in all Vitis germplasm studied. Terpenoids were abundant in V. vinifera with muscat aroma, while esters were dominant in V. labrusca and its hybrids with V. vinifera or V. amurensis. Via principal component analysis, all the grape germplasm studied could be divided into three groups: (1) V. labrusca and its hybrids with V. vinifera or V. amurensis, (2) V. vinifera with muscat aroma and (3) the others, including V. vinifera without muscat aroma plus V. amurensis, and hybrids between V. vinifera and V. thunbergii or V. amurensis. Seasonal quantitative variations of volatiles were observed, but the qualitative volatile composition of the cultivars was consistent.

The composition and content of anthocyanins were surveyed by HPLC–MS for assessing genotypic variation in berry skin of 110 grape cultivars, including 3 species and 5 interspecific hybrids. Twenty-nine anthocyanins were identified. For total anthocyanin content, Vitis vinifera and hybrids of Vitis labrusca and V. vinifera were low, and in general, wild species and rootstock were higher than interspecific hybrids, and wine grapes were higher than table grapes in the same species. As regards the composition of anthocyanins, malvidin-derivatives were the most abundant anthocyanins in the majority of germplasms. All anthocyanins were monoglucoside derivatives in V. vinifera , but all the other Vitis germplasms had both mono- and di-glucoside derivatives. Moreover, peonidin-derivatives and malvidin 3- O -glucoside were, respectively, main anthocyanins in table and wine grapes of V. vinifera . Via principal component analysis, the distribution of the cultivars in a scatter plot depended upon their total anthocyanins content, mono- and di-glucoside derivatives .

Long myosin light chain kinase (L-MLCK) contains five DFRXXL motifs with ability to bind F-actin. Binding stoichiometry data indicated that each DFRXXL motif might bind each G-actin, but its biological significance remained unknown. We hypothesized that L-MLCK might act as an F-actin bundle peptides by its multiple binding sites of 5DFRXXL motifs to actin. In order to characterize F-actin-bundle formation properties of 5DFRXXL region of long myosin light chain kinase, we expressed and purified 5DFRXXL peptides tagged with HA in vitro. The properties of 5DFRXXL peptides binding to myofilaments or F-actin were analyzed by binding stoichiometries assays. The results indicated that 5DFRXXL peptides bound to myofilaments or F-actin with high affinity. KD values of 5DFRXXL binding to myofilaments and F-actin were 0.45 and 0.41 μmol/L, respectively. Cross-linking assay demonstrated that 5DFRXXL peptides could bundle F-actin efficiently. Typical F-actin bundles were observed morphologically through determination of confocal and electron microscopy after adding 5DFRXXL peptides. After transfection of pEGFP-5DFRXXL plasmid into eukaryocyte, spike structure was observed around cell membrane edge. We guess that such structure formation may be attributable to F-actin over-bundle formation caused by 5DFRXXL peptides. Therefore, we suppose that L-MLCK may be a new bundling protein and somehow play a certain role in organization of cell skeleton besides mediating cell contraction by it kinase activity.

0308-8146/$ see front matter 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2010.07.038 DOI of original article: 10.1016/j.foodchem.2010.03.055 * Corresponding author at: Institute of Botany, Chinese Academy of Sciences, Beijing E-mail address: shhli@wbgcas.cn (S. Li). International Partnership Program for Creative Research Teams (Grant No. 0921101001) and the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KSCX2-YW-G075-24).